Zion Dirgantara can easily recall his first day of school in the United States. It was a bright, sunny Tuesday, and terrorists hijacked four commercial planes.

Class for Indonesian-born Dirgantara, then 12, was canceled as parents scrambled to pick up fellow students in Philadelphia. The city was bracketed midway between the ash cloud choking Manhattan and a flaming hole punched through the Pentagon. To the west of Philadelphia, United 93 disintegrated into a Pennsylvania field.

“I realized there was evil in this world, and you have to fight for what is right,” Dirgantara, now 28, told The Washington Post.

Fluent in Indonesian and English, he enlisted in the Army in March 2016 and swore an oath to defend the United States. He has drilled as a reservist cargo specialist since last September.

But Dirgantara’s future in the military and the country now hinges on the ability of Congress to find a way to replace the Deferred Action for Childhood Arrivals program.

President Trump’s decision to end the Obama-era measure sparked fears among advocates that nearly 800,000 immigrants who have lived illegally in the United States since they were children would be subject to removal once their government-issued work permits expire under DACA.

It would be a loss for the Army to bar these recruits, especially as the service struggles to meet recruiting goals. And experts say the relatively small number of foreign recruits have skills with outsize importance to the military’s mission.

The move could affect not only the children of immigrants who crossed the southern border illegally, but those who overstayed visas at a young age, with no other option but to remain here.

Dirgantara, who still lives in Philadelphia, said family problems led his mother to bring him and his brother to the United States on travel visas in the months before Sept. 11, 2001. He did not know he had an unlawful status until he applied for a driver’s license, he said.

As a DACA recipient, Dirgantara enrolled in a Pentagon program, Military Accessions Vital to the National Interest (MAVNI) — an initiative designed to exchange fast-tracked citizenship for crucial medical and language skills among foreign-born recruits. The program has rotated 10,400 troops into the military since 2009.

Additional stringent background investigations introduced last September overwhelmed investigative resources as the Pentagon reviews an internal recommendation to shutter the program completely, leaving open the possibility of the deportation of more than 1,000 recruits who do not have legal status, The Post reported in June.

Dirgantara’s DACA status runs through March 2019, but he still must clear those additional background investigations.

Pentagon spokesman Lt. Col. Paul Haverstick said in an emailed statement that “less than 900″ DACA recipients are either serving or have signed contracts to serve through the MAVNI program.

“The Department of Defense is coordinating with the Departments of Justice and Homeland Security regarding any impact a change in policy may have for DACA recipients,” he said, though it remains unclear what steps those agencies have taken to quell fears of deportation.

Additionally, adversarial nations like China or Russia could learn any potential DACA deportees attempted to enlist in the U.S. military, leaving them exposed to the possibility of harsh treatment or interrogation. Some foreign-born recruits have already sought asylum to avoid deportation, including at least one Iraqi national who fled to Canada to prevent a confrontation with Islamic State militants.

The new Pentagon regulations also have prohibited Dirgantara from reporting to basic training until the background investigation is complete, even though he now serves in uniform.

“Some of us can’t wait for two or three years,” he said.

Margaret Stock, a retired Army officer and immigration lawyer who led MAVNI’s design and implementation, told The Post that drilling reservists like Dirgantara are in a better position to achieve citizenship but that DACA recruits waiting for orders for active-duty training are the most exposed. They must maintain their DACA status, and if the program ends, they have no further legal status to qualify for service.

That puts Dirgantara and hundreds of others in a race against time to avoid deportation back to now unfamiliar nations.

“By definition, DACA recipients are a prescreened pool of people of a higher quality than the average recruit,” Stock said. “They have no criminal background and graduated from high school. And they’re highly motivated to join the military because it’s their only option to stay in the country.”

One recruit told The Post he learned he was undocumented after he told his mother about plans to enlist, but she explained he had no Social Security number. He received DACA status and enlisted for active duty Army service in 2016, though he too has been slowed by the background investigation process.

“I signed the contract in good faith knowing that I may die and pay the ultimate sacrifice for a country that’s trying to kick me out,” the recruit said, speaking on the condition of anonymity for fear of reprisal from the government. He also would not disclose his home country.

“Give me a chance to pay for my parent’s sins,” he said.

Dirgantara, who has spent more than half his life in the United States, is trying to keep busy in his civilian job as a chef while gearing up to watch his beloved Philadelphia Eagles take on the Washington Redskins on Sunday.

His mother died seven years ago, leaving few connections to Indonesia, where he hasn’t been since arriving in the United States 16 years ago. He is at a loss to describe what he would do if he were deported there.

“Indonesia is a foreign country to me,” he said.

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