As a child growing up in Jackson Heights, Queens during the mid-2000s, Antonio Alarcon knew he’d been brought to the U.S. illegally from Mexico. After arriving at age 10, he was kept from school for an entire year because his parents were so afraid of being caught by U.S. immigration officials.

“I was pretty much locked in a room from eight in the morning to 3 p.m.,” the now 25-year-old recalled. “So for a year, I was technically in my room just, like, watching TV and pretending that I was learning English.”

Alarcon’s parents learned he could enroll in his local public school, where he said he felt welcomed. He eventually did learn English and became a top student. When he was preparing to graduate Flushing High School in 2012, his guidance counselor told him he was nominated to apply to prestigious colleges.

But then he learned that he couldn’t attend any of them because he didn’t have a Social Security number.

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“I think that was the moment that I was like, wow, you’ve told me to be a good student,” he said. “But now just because I don't have those nine digits, you are rejecting me from these top 10 institutions, the dream schools I always wanted to go.”

But a few months after Alarcon graduated high school, the federal government began accepting applications for Deferred Action for Childhood Arrivals (DACA), a program President Barack Obama created using an executive order to grant rights to undocumented child immigrants. With DACA, those in good standing could go to college just like legal U.S. residents, as well as obtain working papers and drive. 

About 700,000 immigrants had DACA as of 2017

Alarcon received his first DACA card in 2013 and went on to graduate from LaGuardia Community College and Queens College. 

Then last year, he became one of six plaintiffs from New York who successfully challenged President Donald Trump’s 2017 executive action to end DACA. He and others claimed the Trump administration violated the law by the way it ended the program. Trump claimed Obama exceeded his authority in creating DACA.

On Tuesday, Alarcon and other New York activists will be inside the U.S. Supreme Court when the nine justices hear arguments in the federal government’s appeal of the New York ruling and two similar cases by federal judges in California and Washington, D.C. 

Although they will only be observers in the court, the plaintiffs from all three DACA suits, who met at a gathering last month in Washington, D.C., have been using what will be a national moment to call attention to their cause. 

Carolina Fung Feng, 30, who is taking part in a march from New York to D.C, made it to Baltimore on Friday with more than 30 other New Yorkers. Together, they plan to walk a distance of more than 200 miles in 18 days.

“We have been welcomed by a lot of communities that we’ve come across on our journey but we’ve also encountered a couple of hecklers who yelled mean things to us,” said Fung Feng. They in turn responded by chanting slogans like “Say it loud, say it clear, immigrants are also here.”

She said they stayed overnight at churches and with community organizations. Some people even volunteered to wash their clothes.

Fung Feng, whose parents are Chinese, came from Costa Rica at age 12, and grew up in Washington Heights. She was already in college when DACA was created in 2012, but the program enabled her to work legally and she now holds a job at a public library in Brooklyn helping adults who didn’t finish their high school degrees.

Queens resident Martin Batalla Vidal, 29, was the very first DACA recipient to sue the federal government back in 2016, after the state of Texas successfully won a lawsuit to reduce the duration of DACA work permits from three to two years. While he wanted to march at least part of the way to D.C., he said he can't afford to take off from work.

“At first I was scared like everybody else because I was going up against the government,” he said. “But at the end of the day, somebody has to be brave enough to be the face of the lawsuit.”

Vidal was brought to the U.S. from Mexico when he was seven, and worked for several years after graduating high school when he couldn’t get aid to go to college. He said he was initially skeptical of DACA, worried the government might use it to locate his undocumented mother. But he eventually applied and immediately started getting better jobs.

“Most of the places, they use the E-Verify,” he said, explaining that he was limited to minimum wage jobs at places that didn’t really check for documents. “So once I was able to get that Social Security, I started working in fast food. But in less than a year I was a shift manager and then a supervisor and then [general manager].”

Vidal is now a certified nursing assistant providing rehabilitation to patients with traumatic brain injuries, while finishing a degree at LaGuardia Community College. 

If the Supreme Court sides with the Trump Administration when it issues a decision on DACA next year, the plaintiffs would lose their legal protections, work authorization and could face deportation. Vidal and Alarcon acknowledge that’s a scary prospect.

Alarcon was able to visit family in Mexico by having DACA. He’s now a Census coordinator at Make the Road New York, which is also a plaintiff along with New York, Washington, D.C. and 15 other states. He called immigration the civil rights movement of the 21st century.

“I think there's a lot of fear and a lot of concerns, but we know that is a community,” he said. “We will fight back just as we have been doing over the last three years.”

Vidal said they’ll continue fighting for Congress to give them and millions of other undocumented immigrants legal status. He said polls show most Americans support DACA.

"DACA recipients are nurses, lawyers, doctors,” he said. “We just contribute to the economy just like everybody else.”

Beth Fertig is a senior reporter covering courts and legal affairs at WNYC. You can follow her on Twitter at @bethfertig.