President Donald Trump’s travel ban hits its halfway mark this week, and experts say the administration does not have much to show for it.

After several court setbacks, the Supreme Court allowed the administration to reinstate most of the ban, which runs for a total of 90 days.

There is scant evidence the ban is strengthening national security or laying the foundation for more long-term reforms to immigration vetting, according to over a dozen security and immigration experts and former government officials surveyed by NBC News.

Instead, experts said the travel ban continues to antagonize potential allies without precisely targeting areas that have historically been a source of immigration-related terror. They point to the fact that no nationals of the countries banned have killed an American on U.S. soil in more than 40 years.

Under the order, foreign nationals are banned for 90 days from six countries — Iran, Syria, Sudan, Somalia, Libya, and Yemen — and refugees lacking a link to the U.S. are barred for 120 days.

Demonstrators protest President Trump's travel ban policy outside Hatfield-Jackson Atlanta International Airport on Jan. 29. Christopher Aluka Berry / Reuters file

"The terrorist threat from these countries is vastly overblown," said Alex Nowrasteh, an immigration policy analyst at the CATO Institute. "A lot of the American fear on this is based on what has happened in Europe with terrorist attacks in recent years, even though those attacks have almost entirely not been committed by people from these countries."

The Supreme Court narrowed the ban to protect migrants with a strong relationship with the U.S., such as family ties, and the entire order could still be struck down after the Supreme Court hears oral arguments scheduled for the fall. In July, a Hawaii district court judge ordered that the State Department guidelines include grandparents, grandchildren, brothers-in-law, sisters-in-law, aunts, uncles, nieces, nephews, and cousins of persons in the United States.

Status of the Trump Administration’s Review

The administration initially justified the ban by saying it would relieve government agencies of "investigative burdens," while three government agencies, the departments of Homeland Security and State and the Office of the Director of National Intelligence, conduct a worldwide review and report their findings to the president.

It is hard to know exactly what the administration has done for its review or what recent data tell us about the ban. In an emailed statement, Department of Homeland Security press secretary David Lapan said the agency had completed its review and submitted a report to Trump on July 10.

On Monday, when asked about the report, neither the White House nor the Department of Homeland Security would provide NBC News with a copy.

“The President’s travel order, refugee ceiling and heightened vetting requirements are vital to keeping America safe,” a White House official said. “Foreign terrorists are constantly trying to infiltrate the United States through migratory flows and we cannot allow a sanctuary for terrorists and extremists on our shores and in our communities. The Administration will continue to take necessary and lawful action to keep violent radicals from entering our country.”

While DHS has yet to make any affirmative policy pronouncements, Betsy Lawrence, director of government relations for the American Immigration Lawyers Association, a liberal group, said people are getting stopped at the border more frequently.

"We are hearing about people being questioned more heavily when coming into ports of entry by Customs and Border Patrol," she said.

On July 12, the State Department told consular posts in a cable that the results of the worldwide review had been sent to the president. Although the cable made reference to the report, the administration has said very little publicly about any findings or any formal policy changes.

The administration has not shared, for example, the list of the countries the government deems unwilling or unable to share requested information about their nationals. "Everyone’s kind of waiting with baited breath to see if there will be some kind official announcement related to the new policy," Lawrence added.

As part of the administration’s new visa vetting protocols, the Department of State has suggested a new series of questions that consular officials should ask visa applicants, including sources of funding for their travel from the past 15 years, as well a list of social media platforms the applicant uses.

"Things like having to show a source of funds for travel can be really onerous to be people," Lawrence said.

Has the Ban Secured the Borders?

The main purpose of the ban is to enhance security in the U.S. by stopping terrorists from entry, according to the White House. But Marco Lopez, formerly chief of staff for Customs and Border Protection at the Department of Homeland Security under President Barack Obama, said he believes the ban may be leading to greater insecurity.

"Line supervisors and agents are frustrated with the lack of clarity and they don’t like these blanket statements that everyone from a country is a threat,” he said. "They like to understand what’s the threat and what they should be looking for."

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Protesters rally against the separation of families under President Trump's travel ban in New York on June 29. Alba Vigaray / EPA file

Lopez said officers are pulling people out of the entry lines to do secondary checks to make certain they have proven their case to the embassy and that they have a bona fide relationship with the person in the U.S. they are visiting, as the administration is requiring. Lopez said these extra steps amount to a massive commitment of time and resources. "That’s one less person you have to focus on real threats based on intelligence," Lopez said.

Others argue that the ban has fomented turmoil in our immigration system and undermines confidence in U.S. institutions.

"It matters because the rule of law is affected and it matters because individuals are trying to make informed decisions about what they’re going to do with their lives," said Sarah Paoletti, who directs the transnational legal clinic at the University of Pennsylvania Law School.

But not everyone agrees that the ban clearly makes us less safe.

"It did what it was intended to, which was to give the government the breathing space to review procedures about bringing people in that were potentially very high risk because of the outflow of foreign fighters," said James Carafano, a national security analyst at the conservative Heritage Foundation. Carafano led the Trump administration's Homeland Security transition team after the 2016 election.

What the Numbers Show

The breadth of the ban’s impact is hard to quantify.

Current data that tracks immigrant, tourist and business travel to the United States is not yet publicly available. But data from previous years suggest the number of people entering from the six affected countries is small.

Tourists and business travelers entered the United States approximately 69 million times in 2015, according to Homeland Security's statistics for that year, which is the most recently available. Travelers from the six banned countries accounted for fewer than 50,000 admissions in that same year.

"These are not countries that have a significant immigrant or travel experience to the United States," said Michelle Mittelstadt, communications director for the Migration Policy Institute, a non-partisan Washington-based think tank dedicated to research on the global movement of people.

One area where data is readily available is refugee admissions. Data from the Department of State Bureau of Population, Refugees and Migration shows a dramatic drop in refugee admissions this year from the six countries affected by the travel ban. From Jan. 1, 2017, to Aug. 1, 2017, the United States admitted 7,242 refugees from the six countries, less than half the 14,958 who were admitted last year.

However, the drop in refugee admissions isn’t unique to those six countries. All refugee admissions to the United States are down 40 percent this fiscal year compared to the previous one. Analysts caution that the drop in refugee admissions from the six countries may be dependent on a variety of factors.

"It’s difficult to parse out if these declines are wholly representative of the fact that the Trump administration is seeking to pause refugee resettlement or if some of this pertains to just other factors," Mittelstadt said.

How Refugees Are Affected

As the number of refugees entering declines, the need for refugee sanctuary is at an all-time high. Currently, there are 22.5 million refugees worldwide, and half are under the age of 18, reports the United Nations High Commissioner for Refugees.

Dler is a Kurdish Iraqi who worked with U.S. forces for more than six years in Iraq. As a result, he and his family were threatened by militias and fled to Jordan. "They tried to kill me and kill my family and they threaten me," said Dler, who withheld his last name out of safety concerns. "Because of this, I deserve to go to America to protect my family and my life." Courtesy of IRAP

"It’s been very frustrating for our clients, especially those being persecuted," said Mark Doss, a supervising attorney at the New York-based International Refugee Assistance Project (IRAP), which has opposed the travel ban. "The government is continuously trying to find ways to slow down the process to shut people out who are in need of resettlement, who are trying to get to safety."

One IRAP client is a Kurdish Iraqi named Dler who worked with U.S. forces for more than six years in Iraq. As a result, he and his family were attacked and threatened by militias and fled to Jordan.

"They tried to kill me and kill my family and they threaten me," said Dler, who withheld his last name out of safety concerns, speaking with the help of a translator in a phone interview. "Because of this, I deserve to go to America to protect my family and my life."

Initially, he was denied a Special Immigrant Visa because he had a criminal history of forging documents in order to evade the Iraqi draft in the 1990s.

Dler said he did it because he was the sole provider of his family and anti-Saddam Hussien. He says his father, a Kurdish nationalist, was killed by Hussein. IRAP filed a waiver for him, which the Obama administration granted in December 2016, and he was already in the process of security checks when the first Trump travel ban was issued in on Jan. 27.

He has no family ties that would count as a required bona fide relationship and remains stuck in Amman, Jordan, where he says the government will not give him humanitarian assistance or allow him to work. He has a child but cannot take him to school because he does not have the money to pay the school fees.

"Your life here is as if you are a shadow of a citizen, so of course you are looking for any way to get out," he said.

How Are People Fighting Back?

In the months since the administration’s first rollout of the travel ban, organizations and citizens alike have sought to find ways to both cope and fight back, including through unexpected alliances.

Meanwhile, the U.S. Conference of Catholic Bishops has doubled-down on its support for people of all faiths who are fleeing persecution.

An Iraqi family from Woodbridge, Virginia, welcomes their grandmother at Dulles International Airport in Sterling, Virginia, on Feb. 5. Astrid Riecken / EPA file

"We believe in assisting all those who are vulnerable and fleeing persecution, regardless of their religion," said Bishop Joe Vasquez, chairman of the conference's Committee on Migration, in a statement online.

Muslim-Americans have also taken to social media to share personal stories and photos of cherished family members to push back on what many saw as an attempt to equate their grandparents with terrorists, which led to the trending hashtag #GrandparentsNotTerrorist.

Holly Dagres, an Iranian-American, started the Instagram account, “Banned Grandmas,” to share posts from the original hashtag. Dagres said that as the account became more popular, other Muslim-Americans began to submit their own photos.

"There are a lot of people who aren’t even Muslim who are vocalizing their frustration and embarrassment with the Trump Administration’s handling of this ban," Dagres said. "When they see the pictures of these grandparents, it reminds them of their own grandparents—they see their own grandparents in these photos."

What Will the U.S. Supreme Court Do?

If the ban expires after 90 days and is not renewed, it is possible that the Supreme Court will not make any decision about the ban, because the Court typically does not like to review a law unless it raises an "actual controversy."

If the Court does decide, it will consider two main arguments.

International travelers arrive on June 29, the day that President Trump's limited travel ban, approved by the U.S. Supreme Court, went into effect, at Logan Airport in Boston. Brian Snyder / Reuters file

"Immigration touches on national sovereignty and the [Supreme] Court has been largely loath to second guess the president," said Stephen Yale-Loehr, a Cornell Law School professor and immigration lawyer. "They say the president has more weight than usual and the Constitution has less weight than usual."

On the other hand, the State of Hawaii and International Refugee Assistance Project say that courts may scrutinize the rationale behind a president’s actions.

In fact, many opponents of the ban are skeptical of the ban’s official rationale.

Bernard Harcourt, a law professor at Columbia University, represented a 24-year-old Syrian medical resident stranded in the United Arab Emirates after Trump signed the first travel ban in January.

"It was a pretext," Harcourt said, "a dressing up of anti-Muslim discrimination."

CORRECTION (Aug. 15, 3:17 p.m.): An earlier version of this article misstated on first reference the name of an organization opposing Trump’s travel ban. It is the International Refugee Assistance Project, not International Refugee Project.