After manning a machine gun on a combat helicopter as a U.S. Marine during the liberation of Kuwait, Antonio Romo came back to the United States traumatized by the death and carnage he saw.

He says he turned to alcohol and narcotics to try to quiet the nightmares, and made multiple suicide attempts. With addiction, he fell into dealing, and was arrested for selling cocaine. And after getting out of prison, Romo was deported in 2008 to Mexico, from where he had migrated to Lynwood, California, illegally at age 12.

Today he's part of a group of dozens of U.S. military veterans, most of them former legal residents but noncitizens, who were deported after criminal convictions and who for years have tried to convince multiple administrations to let them return. They acknowledge committing serious crimes such as felony drug dealing, but argue that they did their time and being kicked out of the country amounts to being punished twice.

Now these veterans are pinning their hopes on the new administration of Donald Trump, and their cause presents a sharp conflict for two of the new president's stated priorities: Trump has promised to support the military and veterans; at the same time, he has also moved to ramp up deportations of immigrants in the United States illegally -- particularly those convicted of crimes.

"President Donald Trump has said that he supports veterans, but ..." the 48-year-old Romo said, his voice trailing off. "We are Mexicans. ... I don't know."

Either congressional legislation or a presidential executive order could open the door for Romo and the others.

A White House official declined a request for an official administration comment on the issue. The person, who was not authorized to discuss the matter and spoke on condition of anonymity, said: "The current policy is reflective of those that have transcended administrations from both parties. I do not have any information regarding any changes to that."

In September, then-candidate Trump suggested he would be open to letting immigrants who serve stay in the U.S. even if they came illegally.

"I think that when you serve in the armed forces, that's a special situation, and I could see myself working that out," Trump said at NBC's Commander-in-Chief Forum. "Absolutely."

The United States has recruited foreign-born soldiers since the mid-19th century, and between 1999 and 2008, more than 70,000 of them enlisted, according to a report by the American Civil Liberties Union. Service has provided an expedited path to citizenship, with more than 109,000 veterans becoming naturalized Americans between 2001 and 2015, according to U.S. government statistics.

But that doesn't happen automatically; it's up to the veterans to follow through on the process. Some, like Romo -- who was awarded a medal for the liberation of Kuwait, according to a copy of his discharge order he provided to The Associated Press -- fall through the cracks. And those who commit felonies, which psychologists say are often linked to post-traumatic stress from battle, risk being kicked out of the country.

In 1996, U.S. immigration law was toughened to include around 30 deportable offenses for such cases, including robbery or drug crimes.

The Tijuana-based Deported Veterans Support House says it has documented at least 301 cases of veterans being deported to some 30 countries. More than 60 of them are Mexican.

Hector Barajas, a former paratrooper who was born in Zacatecas state, crossed illegally into the United States at age 7 and served in the Army from 1995 to 2001. He recalled the first time he was deported in 2004, after spending a year-and-a-half in prison for shooting at a vehicle, to Nogales, across the border from Arizona.

"I remember they took me to the border, opened a door and that was it," Barajas said. "You feel lost."

Unaccustomed to speaking Spanish and with no idea of how to make a living, Barajas crossed back into the States six months later. He was deported again in 2010, moved to Tijuana and founded the Support House, nicknamed "the bunker."

Many deported vets gravitate to Tijuana to be closer to relatives in Southern California, some of whom are U.S. citizens and can cross the border to visit.

Often the first door they knock on is "the bunker," a stone-facade shop decorated with American flags.

Barajas puts the veterans in touch with lawyers who help them receive pensions when possible, with psychologists who help them overcome trauma and addiction, and with job counseling programs. Above all the house is something of a support community.

Like many deported Mexicans who spent decades in the United States, some veterans struggle to find work in an unfamiliar country. Others are hired by Mexico-based call centers, prized for their fluent English. Deported veterans have died in Mexico, or been forced to watch from afar as loved ones die on the other side of the border.

Still many say they wouldn't hesitate to serve again if given the chance.

"I would enlist all over again," Romo said.

"Where do I sign up?" said Barajas.

The ACLU and some lawmakers have tried to build bipartisan support for stopping or reducing veteran deportations in the past. But others say they like the current laws just fine.

"We owe all the men and women who have fought for our nation an enormous debt of gratitude and respect. Prior military service alone, however, cannot create a blanket exemption from the laws of our country," said John Shimkus, a retired Army lieutenant colonel and Republican congressman from Illinois. "The current policy, which requires senior immigration officials to review each situation in which a green-card-holding veteran faces deportation, allows for the unique circumstances of each case to be considered."

California state Assemblywoman Lorena Gonzalez, a San Diego Democrat married to a Marine vet who served in Iraq, has proposed a legal fund to help deported vets apply for readmission.

The U.S. Citizenship and Immigration Services said it does not have figures on how many deported veterans have requested naturalization and that it considers each petition individually.

Regardless of what happens, Barajas hopes to open another "bunker" to serve vets in Ciudad Juarez, across the border from El Paso, Texas, and to lobby both Congress and the executive branch on the issue.

Romo had become a legal resident before enlisting in the military and was living in San Diego when his legal troubles began. He was sent to federal prison in Big Spring, Texas, in 2001, convicted of conspiracy to distribute and sell cocaine. He said prison made him feel human again because it was there that he first got psychological help.

When he got out, a judge broke the news that he had not automatically become a citizen through his military service, but said he could apply to become one. He began working with a lawyer.

But Romo was deported five days before an appointment to settle his immigration status and deposited across the Rio Grande before dawn one day in July 2008 into Tamaulipas, a key smuggling corridor for drug cartels and one of Mexico's most violent states.

"I was scared," Romo said.

Today, from his Tijuana apartment decorated with replicas of guns, Romo can see the wall that separates him from family on the other side including his 22-year-old daughter. Darkly, he mused that ultimately he may only go home in a coffin: The U.S. awards posthumous citizenship to combat veterans who have not been convicted of crimes that carry a possible death penalty or life sentence.

"We offered our lives, in exchange for nothing," Romo said.

With their hopes on Washington, some still talk of respect for the chain of command.

"Donald Trump is the commander in chief, and we have to work with that," Barajas said. "We are soldiers."