Kirti Tiwari was elated when he learned last year that he’d been nominated by his higher-ups at the United States Army to become a NASA astronaut. Tiwari, who first enlisted in the military in 2014, was excited by the prospect of what he felt was a huge career advancement opportunity. “I always had this idea of wearing a uniform,” he says.

Then Donald Trump won the presidency, and Tiwari’s dreams came crashing down.

Despite glowing recommendations from members of the military—including a statement by his commanding officer that read: “[It would be an extreme disservice to the Army and our country to not invest in this intelligent and confident young leader”—Tiwari ran into a new blanket policy by the Department of Defense that tightened security requirements to such a degree that they effectively denied him, and thousands of other naturalized citizens like him, the clearance necessary to serve his new country.

Tiwari, 29, is an Indian immigrant enrolled in Military Accessions Vital to the National Interest, a military recruitment pipeline that offers expedited citizenship to foreign-born soldiers with specialized language or medical skills. The program has been open to non-citizens fluent in highly sought-after languages like Arabic, Chinese, or Hindi, and medical professionals needed to cover shortages in the military’s roster.

Tiwari, who first came to the U.S. on a student visa, qualified for the program on account of both his fluency in Hindi and his academic performance. Prior to enlisting, he had earned a master’s degree in molecular biology from the University of Houston, and worked as a research specialist at Baylor College of Medicine and Texas Children’s Hospital. He enlisted in June of 2014; one year later, he was naturalized through the Army after completing basic combat training and advanced individual training. In 2016, after a months-long process, Tiwari simultaneously applied for a NASA astronaut candidate program through the Army and a military microbiologist posting.

A few months later, Tiwari learned the Army had selected him as a microbiologist and also nominated him for the NASA astronaut program. Tiwari was working as an Army health-care specialist at a military base near Tacoma, Washington, where he was told that he had been retroactively declared ineligible for either career opportunity—precisely because he was a foreign-born recruit.

In September of 2016, a Department of Defense memo appeared ordering “enhanced security clearance checks” for MAVNI recruits, citing security concerns. The soldiers were no longer eligible for interim security clearances until they completed their first enlistment, the memo declared. For soldiers like Tiwari, who depended on these security clearances to qualify for military jobs, this meant career opportunities would be compromised. For others, many of whom had yet to naturalize despite pledging their careers and loyalty to the U.S. Army, it imperiled their path to citizenship. Soon, reports surfaced that soldiers could no longer ship out to basic training without completing additional security checks. However, for the vast majority of recruits, the problem was not just the application of more security checks, but the fact that the Army had seemingly stopped processing the security checks in a timely or efficient manner—many reported that they weren’t properly scheduled for checks, effectively stalling their military service. In the most extreme cases, the immigration statuses of some recruits lapsed altogether, subjecting them to possible deportation merely for having attempted to join the Army.

The ensuing chaos and disruptions in the program triggered lawsuits from both foreign-born soldiers still awaiting citizenship as promised under MAVNI and soldiers who had managed to naturalize and were now blocked from career advancement by new security clearance requirements.

Last month, the news went from bad to worse: Some soldiers waiting to ship out to basic training found out that their enlistment contracts had been killed without warning, leaving many foreign soldiers stranded in the U.S. with no back-up plan.

“The program’s dead, basically,” says lawyer Margaret Stock, a retired lieutenant colonel who helped develop the military’s MAVNI program. Given the Trump administration’s xenophobic rhetoric and climate of hostility toward immigrants, Stock says the chances of the program’s resuscitation aren’t great.

There have been periodic concerns about the security of MAVNI since its creation in 2008, and the program has, in fact, been suspended on several occasions: Following the November of 2009 Fort Hood shooting, in which U.S.-born soldier Nidal Hasan murdered 13 people (including immigrants in the military), the Obama administration put a pause the MAVNI program. The program was re-instated three years later and the U.S. naturalized almost 10,000 MAVNIs last year. Some continue to question the vetting process of foreign-born soldiers.

Immigrants eligible for the program must already have been in the U.S. legally for a minimum of two years in a non-immigrant category, or under asylum or temporary protection status. By the time MAVNI recruits enter the U.S., they have already undergone post-9/11 security vetting from the Department of State and the Department of Homeland Security. DHS also performs an individual review before permitting immigrants to sign up for recruitment. After signing a contract, immigrants’ names are screened against multiple databases of terrorists and criminals’ names in the National Intelligence Agency Check, a process that can span up to six months. “I haven’t heard of a single case of any MAVNI being arrested on terrorism charges,” Stock says.