Grand Forks, North Dakota (CNN) Mehdi Ostadhassan was at an academic conference when he received a mysterious phone call from the FBI.

The Iranian native had moved to Grand Forks, North Dakota, in 2009 to study petroleum engineering. After marrying an American citizen and becoming an assistant professor at the University of North Dakota, Ostadhassan applied for a green card.

But his interview with an immigration officer in the spring 2014 was abruptly cancelled without explanation. And then, months later, came this call..

"This is Agent Richard from the FBI," said the voice on the line, Ostadhassan recalled. "I'd like to talk to you about your recent trip to Iran."

Five years later, Ostadhassan still has no green card. Instead, he is tangled in a web spun by forces larger than himself, including an obscure national security program, an ACLU lawsuit against the US government and escalating tensions between the United States and Iran.

There have been nights when Ostadhassan's frustrations overflowed and he's chucked his binder of immigration papers into the trash. But then he thinks of his thriving career, the American family he loves and his desire to raise his children in the country that has given him everything.

Or, almost everything.

Mehdi Ostadhassan in his office at the University of North Dakota, where he teaches petroleum engineering.

"All I'm asking for is due process," Ostadhassan said. "If I have done something wrong, then kick me out or present my case to an immigration judge."

But the US government seems to be more interested in Ostadhassan's past than his future.

His instinct on that October day in 2014 was to meet with the agent. He had nothing to hide.

Then Ostadhassan started Googling. He didn't like what he found.

Living in limbo

Ostadhassan and his family live in a small apartment near the outskirts of Grand Forks, where the strip malls meet the soybean fields. A toddler's toys lie in neat piles. College textbooks, bills and two big binders full of immigration documents cover the dining room table.

Colored pins on a world map mark the places Ostadhassan and his family have visited. His pin hasn't left the United States since 2014, when he returned from his honeymoon in Iran.

Back then, Ostadhassan had been optimistic about his prospects in the United States. Now he swings on a pendulum of emotions: hope, despair, hope, despair.

"It's like living in limbo," Ostadhassan said. "You never know what's going to happen, or when."

A trial in federal court, set for March 2020 in Seattle, will shine a light on the obscure CARRP program.

The ACLU, which is representing Ostadhassan in a landmark legal case, says his uncertainty can be traced to an obscure national security program called CARRP, which stands for Controlled Application Review and Resolution Program.

The program, which began in 2008 under President George W. Bush, is used by US Citizenship and Immigration Services (USCIS) to vet immigrants it classifies as potential national security concerns before granting green cards, citizenship or asylum.

But not much is known about how CARRP actually works or who it selects for additional levels of scrutiny. USCIS told CNN they would not comment on questions about CARRP.

Immigrants and their lawyers are often kept in the dark about CARRP, according to court documents and depositions of USCIS officers. The program is not found in any public statutes or agency regulations. Even seasoned immigration experts told CNN they had no idea CARRP existed.

The ACLU argues that CARRP is discriminatory and illegal. The Justice Department counters that CARRP is essential to maintaining national security.

Immigrants have yet to successfully challenge the program in court. Each time they've tried, USCIS has quickly resolved their complaints, leaving them without standing to sue.

Next March, CARRP will finally have its day in court, when a federal trial, Wagafe v. Trump, begins in Seattle. It's a class action suit, which means Ostadhassan's legal fight extends to thousands of immigrants who suspect CARRP has played a role in delaying or denying their applications to live and work in the United States.

Already, the lawsuit has cracked open a window into CARRP, which has been used to vet nearly 42,000 immigrants since 2008, according to documents obtained by CNN through a Freedom of Information Act (FOIA) request.

We are not saying that the government can't investigate national security concerns. But the individual should have the right to challenge that information. Sameer Ahmed, former ACLU attorney

Outside the courtroom, the controversy over CARRP contains some of the most contentious issues of the Trump era, namely immigration, national security and allegations of anti-Muslim discrimination.

In North Dakota, Ostadhassan tries to follow the legal cat and mouse between the ACLU and Justice Department.

But by the time his trial rolls around, he may have already left the country.

Flirting about physics

Ostadhassan is laid-back and fit, a workaholic who feels antsy when he doesn't hit the gym. At 36, his black hair is graying at the temples. A petroleum engineer and devout Muslim, his personality mixes earthbound practicality with heaven-sighted certitude.

In his office at the University of North Dakota, among the complicated equations colorfully drawn on glass walls, hangs an Iranian poem reminding him that God's eyes see all.

"God has never stopped paying attention to me," Ostadhassan said on a warm day last year. "I have seen it, have felt it with every cell of my body and my soul."

Ostadhassan's wife, Bailey Bubach, can keep a close eye on him as well. Her office is across the hall, where she's a college administrator and professional adviser in the petroleum engineering department.

Ostadhassan met Bubach, who is friendly and forthright, at a university picnic when she asked him a question about physics.

Ostadhassan's wife, Bailey Bubach, was raised Catholic but converted to Islam.

"I was trying really hard to flirt with him," Bubach said with a laugh. "But he didn't pick up on it."

"I totally didn't get it," Ostadhassan agreed. "Who flirts about physics?"

Raised Catholic, Bubach converted to Islam before she and Ostadhassan began dating. Like Ostadhassan, she's now a Shiite Muslim. A bright blue hijab matches her bright blue eyes.

In 2014, after Ostadhassan earned his doctorate in petroleum engineering, the couple married. A month later, he applied for a green card.

The next step should have been an appointment with US Citizenship and Immigration Services in St. Paul, Minnesota, the closest field office to North Dakota.

But after waiting for two hours in the lobby, they were told the appointment had been canceled. They were not told why, the couple said.

Perplexed, the newlyweds drove back to North Dakota.

It's like the No Fly List

After five months passed with no word from USCIS, Ostadhassan and Bubach tried to schedule another appointment in St. Paul.

When they arrived at the field office, a clerk told them that a "third party" was investigating their applications. (Bubach had applied to have Ostadhassan recognized as her husband, a necessary step toward obtaining a family-based green card.)

The ACLU says the "third party" was likely the FBI. It was the first indication, they said, that Ostadhassan may have been ensnared by CARRP.

An FBI spokesperson declined to answer questions about Ostadhassan or comment about the agency's interactions with him. USCIS told CNN they would not comment on questions about Ostadhassan because of his court case.

In a statement, USCIS spokesman Daniel Hetlage said: "As part of our mission of safeguarding the integrity of the nation's lawful immigration system, securing the homeland and ensuring fair and proper adjudication, USCIS identifies, vets and adjudicates applications that present national security or egregious public safety concerns in accordance with the law."

The ACLU argues that CARRP is mostly used to prevent Muslims and immigrants from Muslim-majority countries from obtaining benefits open to others.

Between April of 2008 and January 2016, USCIS opened nearly 42,000 CARRP cases, according to documents obtained by CNN through a FOIA request. The top five countries of origin all have large Muslim populations: Pakistan, Iraq, India, Iran and Yemen.

"God has never stopped paying attention to me," Ostadhassan says.

One USCIS document lists 20 countries from which immigrants were subjected to CARRP from 2009-2012. In all except one -- Sri Lanka -- Muslims form a majority of the population. In May of 2018, CNN asked USCIS for an updated list but has not received the information.

As of April 2018, more than 4,800 immigrants were being investigated through CARRP, according to documents filed by the Justice Department in Ostadhassan's court case. USCIS has not responded to CNN's requests for more recent numbers.

Congressional guidelines instruct immigration officials to process most applications within 180 days of when they are filed. But for some immigrants the process can last for years, without their ever knowing why.

"We are not saying that the government can't investigate national security concerns," said Sameer Ahmed, a former ACLU attorney who worked on Ostadhassan's lawsuit. "But the individual should have the right to challenge that information and the right to be heard."

Ahmed compared CARRP to the No Fly List, a program that prevents people suspected of presenting national security concerns from boarding commercial airplanes that enter US airspace. After extensive litigation, the government must now tell US citizens and permanent residents if they are on the list and give them an opportunity to respond.

When he drove home from the USCIS office in 2014, Ostadhassan had never heard of CARRP. But he knew his immigration status was in trouble.

Fallout from the FBI call

On that call in 2014, the FBI agent suggested they meet at a popular coffee shop in Grand Forks. Ostadhassan agreed.

But after he hung up, Ostadhassan searched online, where he found reports accusing FBI agents of offering to help immigrants if they agreed to inform on fellow Muslims. An FBI spokesperson declined to comment on the accusations.

Worried that the FBI might ask the same of him, Ostadhassan started looking for a lawyer.

Through the University of North Dakota's website he found Sabrina Balgamwalla, who supervised its immigrants' rights clinic at the time. She now directs the Asylum and Immigration Law Clinic at Wayne State University in Detroit.

Balgamwalla promptly replied to Ostadhassan's email: Don't even think about meeting with the FBI -- at least, not without a lawyer.

"Mehdi was very concerned about following the rules and doing the right thing," Balgamwalla said. "He felt like he had an obligation to meet with the FBI agent."

Balgamwalla returned the FBI agent's call on Ostadhassan's behalf, asking what the proposed meeting would be about.

"It's totally voluntary," she recalled the agent answering.

Ostadhassan and his wife have built years of memories in the US.

"Yeah, but what's it about?" she pressed. "I'm happy to help with any questions you may have."

The agent repeated that the meeting was voluntary, and that Ostadhassan was free to decline, Balgamwalla recalled.

"And that was the end of the call," she said.

The couple said they were willing to meet with the FBI if the agent had told them more about what he wanted.

"The weird thing here is that they wanted to meet with him alone," Bubach said. "If there were something they really wanted to ask him, why wouldn't they deal with his lawyer?"

The FBI declined to comment about this interaction.

After talking to the FBI agent, Balgamwalla was troubled. Though she had been practicing law for seven years and specializes in immigration, she had never heard of CARRP.

Balgamwalla wasn't alone. Even the ACLU discovered the program almost by accident.

How CARRP works

During a trial in 2011 for a Muslim immigrant who sued USCIS over lengthy delays in his application for citizenship, a USCIS field officer let slip that the immigrant was being vetted through CARRP. (A USCIS leader said the field officer's comment "should not have been made," according to court documents.)

"CARRP, what's that?" thought ACLU attorney Jennie Pasquarella, who was present for the field officer's deposition. Using the courts and the Freedom of Information Act, Pasquarella started to piece the puzzle together.

After the terrorist attacks of September 11, 2001, immigration officials were required to run all applications for immigration benefits through new security checks. For a time, they used the FBI's National Name Check, which led to a massive backlog in adjudicating applications.

In 2008, in response to several lawsuits across the country challenging the delays, federal officials agreed to clear out the backlog, finally allowing many applications to be adjudicated. At the same time, USCIS adopted CARRP to process potential national security concerns, instituting new criteria and vetting procedures.

CARRP is complicated and somewhat opaque. USCIS still hasn't divulged everything about the program. Most of what we know comes from USCIS documents obtained by the ACLU and CNN through FOIA requests.

According to those documents, CARRP basically works in four stages, from identifying potential national security risks to judging whether immigrants can stay in the United States. Along the way, USCIS consults with counterterrorism databases and officials inside agencies such as the FBI.

The couple with their son Elijah, 3.

A series of security backstops are built into the system, and if an immigrant is put on the "CARRP track," USCIS officials are not allowed to grant green cards or citizenship until a full investigation is completed. That can take years.

In CARRP training documents obtained by CNN, the red flags USCIS officers are told to look for are fairly broad. They range from an "articulable link" to a terrorist group to "unusual travel patterns," and training in biology, chemistry or foreign languages.

The ACLU argues that there are a number of problems with this approach.

The Terrorist Watch List and other federal databases are notoriously unreliable, the ACLU argues. The late Sen. Ted Kennedy, Rep. John Lewis and an 18-month old child have all been snared by the anti-terrorist dragnet at times, appearing on the No Fly List.

Also, some FBI files contain the names not only of suspects but also of informants, meaning that immigrants could be subject to CARRP even if they are helping the US government, according to the ACLU.

As Mehdi Ostadhassan learned about CARRP's scrutiny of Muslim immigrants, he began to suspect that his faith played a significant role in his immigration saga.

What happened next would only sharpen those suspicions.

The mysterious man with the badge

In September 2015 -- a year and a half after USCIS cancelled their first interview without explanation -- Ostadhassan and Bubach finally met with immigration officials in St. Paul.

The ACLU told Balgamwalla, the couple's lawyer, that the interview might not follow the usual process for marriage-based green cards.

It differed in two big ways, the attorney recalled.

"We had been warned that the interview might be recorded, and it certainly was," she said. "That has not been the case for any other marriage-based green card interview I have ever sat in on. Usually, there is no need to have a video record."

The second difference was the presence of an unidentified man in the room with the USCIS field officer.

"His name badge was turned facing toward him," Balgamwalla recalled, making it impossible to see his name or occupation, "which I thought was unusual."

After the field officer asked questions, Balgamwalla said, the second man stepped in.

Ostadhassan has compiled stacks of documents about his efforts to remain in the US.

Bubach remembers the second man as "aggressive," but Balgamwalla did not contest his presence. She was worried that she might be asked to leave, leaving the couple without a lawyer present.

Ostadhassan said he does not think the unidentified man was the FBI agent who called him but isn't sure.

Ostadhassan, Bubach and Balgamwalla all say the second man asked a lot about the couple's faith, their travels and Ostadhassan's work as a petroleum engineer.

Bubach said she was asked whether Ostadhassan had coerced her to convert and quizzed on the number of Islamic centers and mosques the couple had visited on their travels.

"Unfortunately for them, that number was zero," Bubach said.

She and Ostadhassan said they left the USCIS interviews confused. Few of the questions were actually about their marriage, the basis of his green-card application.

But the government had more questions about Ostadhassan's past.

The class action lawsuit

A few months later, Ostadhassan and Bubach received a letter asking for more information. USCIS wanted to know about Ostadhassan's previous marriage in Iran.

Ostadhassan says the union was hasty and unhappy -- over in a year. He was 20 at the time.

But USCIS asked Bubach for paperwork proving that her husband's previous marriage had been legally dissolved.

Ostadhassan contacted family in Iran, trying to track down divorce records, to little avail.

Five months later, USCIS told Bubach it intended to deny her application to establish Ostadhassan as her husband. Without that, his green card would also be denied.

But Bubach was pregnant with the couple's first child and wasn't ready to give up. She and Ostadhassan pressed relatives in Iran to track down the documents.

That summer, Bubach gave birth to a son named Elijah, and the family started looking for a bigger place to live.

Bubach said the couple was pre-approved for a loan, but the process faltered because Ostadhassan didn't have a green card, proof that he could continue to live and work in the United States.

Everybody in my family is confused. Because it doesn't make sense, right? They say 'OK, he's here, he's working, he's a professor. He's benefiting the community.' Bailey Bubach

Their dream of a little house on the Dakota prairie was dashed.

During the years USCIS vetted his green card application, Ostadhassan had been allowed to apply for a temporary work permit, which is valid for a year.

It can take months for USCIS to approve and mail the permits, so each fall he has applied for a new permit and waited anxiously, hoping it will arrive before his previous permit expires.

One spring was particularly frustrating, Ostadhassan said. First, he received a letter telling him his work permit had been approved. Then he received a second letter saying it was being held up. A few days later, the permit arrived in the mail, he said.

"It's saddening every year when this time comes around," said Duane Johnson, Bubach's stepfather. "Bailey and Mehdi get so stressed out."

Bubach said it can be difficult to talk to her family about Ostadhassan's struggles.

"Everybody in my family is confused. Because it doesn't make sense, right? They say 'OK, he's here, he's working, he's a professor. He's benefiting the community.'

"They ask us continuously, 'Can't you ask the senator to do something? Can't you ask this person to do anything?'"

Bubach and her family said they have reached out to congressional representatives and been told that Congress has no power to intervene in USCIS investigations. Bubach even wrote to President Trump asking for help in her husband's case. The White House referred her letter to USCIS.

"The reality is nobody can do anything," Bubach said.

Bubach: "The reality is nobody can do anything (for us)."

There was one thing they could do, Balgamwalla suggested. She told Ostadhassan and Bubach the ACLU was preparing a class action suit challenging CARRP.

But there were risks.

Balgamwalla warned the couple that joining the suit might prompt USCIS to process Ostadhassan's green card application, but he might not like the result.

USCIS has far more discretion to deny green cards than citizenship applicants, who have the right to challenge their decisions in court. Green card applicants do not.

But by the end of 2016, two years into his immigration saga, Ostadhassan was frustrated and saw few other options.

He agreed to join the suit. It was filed in 2017, a few days after President Trump took office.

The Basij problem

In March of 2017, after 11 months of silence from USCIS, Ostadhassan and Bubach received a letter from the agency.

Ostadhassan tore open the envelope.

USCIS had approved of Bubach's application naming Ostadhassan as her legal spouse. It was a step toward obtaining a green card, but far from the last one.

A few weeks later, they received another letter from USCIS.

Again, Ostadhassan's heart pounded. Again, it wasn't the news he wanted to hear.

The letter said USCIS intended to deny Ostadhassan's green card application.

"I thought it was the end of my life in the United States," he said.

USCIS cited several reasons.

First, when Ostadhassan filled out student-visa forms in 2009, he failed to list his mandatory service in the Iranian Air Force

Ostadhassan calls his military service a "joke." He said he spent five months doing clerical duty and teaching the Quran. He left for a job in France before completing the service requirement.

"I didn't even learn to fire a gun," he said.

Ostadhassan shows his US work permit, which expires this month.

Ostadhassan said he didn't consider his service "military training" and thus didn't originally mention it on his student visa or green card application. He later amended his green card application after hiring Balgamwalla, who told him to include all of his past associations.

But USCIS devoted most of their its letter to something else: Ostadhassan's membership in an Iranian group -- the Basij -- accused of rampant human rights abuses.

Ostadhassan said he was never involved in any of that when he was a member, from 1993-2000. At the time, he was 10-17 years old.

Raised by teachers in Karaj, a suburb of Tehran, Ostadhassan said the Basij provided the only outlet for religious youths in his area.

"I wanted to participate in the Quran memorization competitions that Basij held for high school students," he said. "That's it."

Ostadhassan said he was only a member of "pupil Basij," which does no policing, and quit the group when he entered college.

Instead, Ostadhassan said he joined an opponent of the Basij, the Islamic Students Association, which has protested for greater religious, political and academic freedom in Iran.

"I thought it was time for me to be an independent thinker," he said.

Saeid Golkar, author of "Captive Society: The Basij Militia and Social Control in Iran," said the Basij is a complex organization. It is split into 22 different branches, one of which, called "Baby Basij," recruits toddlers as young as 2. Some branches are involved in human rights abuses, while others are not, he said.

USCIS did not accuse Ostadhassan of committing any human rights abuses himself but said his membership in the Basij was "a significant factor" in rejecting his green card application.

Ostadhassan said the letter left him baffled. He had amended his applications, which is allowed under US immigration law, to include his membership in the Basij.

"I told them myself that I was a member of Basij," Ostadhassan said. "I didn't have to do that. And now they are holding it against me?"

Meanwhile, in June 2017, the judge presiding over Ostadhassan's class action suit made a huge decision in his favor.

A 'blatant attempt'

To understand why the judge's decision was significant, it helps to look at another aspect of CARRP: how difficult it has been to challenge in court.

Jim Hacking, an immigration lawyer in Missouri, said he's handled dozens of cases where he believes CARRP has been used to vet Muslim immigrants, leading to lengthy delays in adjudicating their applications.

But when he files suit on behalf of the immigrants, specifically mentioning CARRP as a concern, USCIS suddenly speeds up its timetable, Hacking said. It quickly approves or denies the application, leaving the plaintiff with no reason or legal standing to sue over CARRP.

"In most cases, the lawsuit itself is enough to get things moving," Hacking said. "We ask a judge to declare CARRP unconstitutional, and USCIS doesn't want that, so they move the cases along."

The Justice Department seemed to employ a similar strategy in Ostadhassan's lawsuit.

One of Ostadhassan's fellow plaintiffs in the class action suit was Abdiqafar Wagafe, a Somali-American air traffic controller in Seattle who applied to become a US citizen in 2013.

Ostadhassan and Bubach dropping off their son at daycare.

Wagafe waited four years for his citizenship interview with USCIS. Five days after he joined Ostadhassan's class action suit, a USCIS official called to schedule the appointment. Soon after, he was granted citizenship.

Every time the ACLU added more plaintiffs, USCIS would quickly process their applications. Within five months, USCIS had processed every plaintiff in the class action suit.

The Justice Department then urged the judge to dismiss the case, arguing that the plaintiffs lacked standing because their complaints had been dealt with.

The judge didn't agree.

"USCIS has now acted on all of the applications of the named plaintiffs, after up to three and a half years of inactivity," wrote Judge Richard Jones of the Western District of Washington in Seattle.

"Curiously, USCIS's actions on these applications took place almost immediately after Plaintiffs were added as proposed class representatives."

Such a "blatant attempt to moot Plaintiffs' claims," Jones said in June of 2017, "will not gain purchase with this Court."

Suspicions and doubts

On October 27, 2017, Ostadhassan's green-card application was officially denied.

He had been asked on US applications whether he had ever "performed" military service, not whether he had completed it, USCIS said.

"Your explanation as to why you failed to disclose your military history in response to this question is not credible," USCIS wrote.

Again, the Basij was a big factor in Ostadhassan's rejection.

At his interview with USCIS, back in 2015, Ostadhassan said he had been a member of the Basij's "student" faction, USCIS said in their rejection letter.

Later, Ostadhassan changed that to the Basij's "pupil" section, saying it was more accurate. "Pupil" refers to Basij members in high school; "student" refers to college members.

The government has sought proof that Ostadhassan was divorced from his first wife.

But there's a more important distinction, USCIS said.

"Student" Basij members "operate on college campuses in Iran where student demonstrators are often attacked by student members of the paramilitary Basij organization," the agency said.

USCIS said they now had "serious doubts" about Ostadhassan's credibility, essentially saying it did not believe that he was only a member of Basij during high school.

What's more, USCIS said Ostadhassan's lawful non-immigrant status had expired.

"You are not authorized to remain in the United States and should make arrangements to depart as soon as possible," USCIS said in the letter.

Ostadhassan's lawsuit with the ACLU was still ongoing, but the couple had to make a decision: Should they leave the US or stay and fight?

'One of the worst nights of my life'

Ostadhassan re-applied for a green card in December 2017.

In a sense, he was trying to use the complexity and size of USCIS to his advantage, hoping that while his new application was pending he would at least be issued a new work permit.

But in March 2018, six months after his first green card application was rejected, Ostadhassan's work permit expired.

Because he could no longer work, the family worried about their finances. They had some money saved, but not nearly enough, especially with a young child to care for.

Bubach suggested they find a smaller, less expensive apartment.

Ostadhassan went to see his landlord, Christopher Kiley, who offered to lower the rent by $400 a month.

Ostadhassan choked up, thanking Kiley profusely.

"I sympathized with him," Kiley recalled. "He is such a respectable young man and father and husband, and he had something happen to him that is completely beyond his control."

Ostadhassan says the constant worry about his immigration status has taken a toll.

But even with the reduced rent, there were tough days ahead.

During one frazzled moment, Ostadhassan trashed the family's thick binder of immigration documents.

Another time, he and Bubach got into a fight in their car.

"I told her, 'I don't want to hear anything about work, I'm gone. Just let me get out of the car.'"

Bubach stopped and let him out. Ostadhassan walked to the nearest mosque, where he sat in a corner with his head in his hands, crying.

"I just kept thinking about my mother," he recalled, "and how much I wanted to see her."

Bubach picked up their son from daycare and drove slowly through Grand Forks, looking for her husband, whose smartphone battery had died.

Hours later, Bubach returned home. When she saw Ostadhassan standing in their living room, she burst into tears.

"That was one of the worst nights of my life," he said.

His thriving career

One of the ironies of Ostadhassan's saga is that, even as his battle with USCIS has intensified, his career has thrived -- with some help from the US government.

Ostadhassan estimates that, beginning with his graduate studies at the University of North Dakota, private and public sources in the United States have contributed about $1 million to his education and research.

Several research projects he's working on have received funding directly from the US government, including an agreement signed last year with the US Geological Survey. The agreement, which lists Ostadhassan as a principal investigator, is to study unconventional petroleum systems "to benefit the people of the United States," according to a copy obtained by CNN.

"The United States has given me everything: a career, a family, a life," Ostadhassan said. "That's part of why I want to stay in this country. I want to give something back. And I believe that I am."

Ostadhassan has also used his interests in engineering and medical science to study new ways of diagnosing ailments like cancer and Lyme's disease. His ideas are promising enough to pique the interest of colleagues in the University of North Dakota's medical school, who have received funding to test them.

But the shadow of Ostadhassan's immigration troubles never seems to lift.

Ostadhassan: "The United States has given me everything: a career, a family, a life."

One day, he saw a moving truck parked near his apartment. For a moment he feared the government had come to deport him.

But USCIS seems to be in no hurry to do that.

Usually, when USCIS rejects a green card application, the government begins the process of removing the immigrant from the country.

But more than a year after Ostadhassan's first green card was denied, USCIS has yet to give him any information about removal proceedings or even schedule a court date to begin the process.

Another setback

This April, Balgamwalla received a large envelope from USCIS in the mail.

"My heart just sank," she said.

It was another rejection of Ostadhassan's green card application, citing the previous rejection.

Just a few days before, Ostadhassan had received more unwelcome news.

On April 8, the Trump administration designated the Iranian Revolutionary Guard and its subsidiary organizations, including the Basij, as foreign terrorist organizations. The move was seen by many as a way to bolster Israeli Prime Minister Benyamin Netanyahu's reelection race. On Twitter, Netanyahu thanked Trump for "accepting another important request of mine."

All I'm asking for is due process. If I have done something wrong, then kick me out or present my case to an immigration judge. Mehdi Ostadhassan

Ostadhassan asked Balgamwalla what it would mean for his prospects in the United States.

It's not good, she replied.

"Now that the Basij has been labeled a terrorist organization, even if he tried to reapply for a green card under another administration, that's really not good for him," Balgamwalla said.

"What does that mean for the next six months of his life? None of us know."

The final deadline?

In one sense, Ostadhassan's second application for a green card worked. He received another work permit in April 2018, buying him at least a little time for this family to decide their fate. It expires on October 5.

Because he has tenure, Ostadhassan doesn't think he'll immediately lose his job. But it's only a matter of time, he said.

David Dodds, a spokesman for the University of North Dakota, said Ostadhassan's contract with this university runs through the 2019-2020 academic year, but otherwise declined to comment.

Meanwhile, Ostadhassan has received a lucrative offer to work in China, including an apartment, car, daycare, a good salary and top-notch laboratory equipment.

But he doesn't want to go.

The family at home. Bubach is pregnant with their second child.

"To work for a US adversary, that doesn't feel right."

Even after all he's been through during these past six years, Ostadhassan said he feels loyal to the United States. He cherishes the freedom to worship and believe as he pleases, even though he suspects Islam has played a major role in his CARRP case.

But if Ostadhassan can't work, he can't stay in the US.

He and Bubach are expecting another child this year, and the stress is getting to them. When Ostadhassan's work permit expires, so will his driver's license.

"How will I even be able to drive my pregnant wife to the hospital?" he asked.

Ostadhassan would like his children to be educated in the United States, and his dream is to be there when they walk across the stage to receive college diplomas.

But Ostadhassan and Bubach have set a deadline. If his immigration saga is not resolved by January they are going to leave the country, before his court case even starts.

His family will spend some time in Iran, he said, and then fly to China.

Until then, he's going to fight to stay.