To stay in America, millions of undocumented immigrants turned over their personal details to the government on the promise Washington wouldn't use it against them. Now, Trump has betrayed that promise. Julián Gustavo Gómez knew it would happen.

Gómez is a former DACA recipient—he received his green card just a few weeks ago—a proud American, and the national campus engagement manager for Define American, a non-profit working to change the way Americans view immigrants. Weeks after Trump's election in 2016, The Washington Post published an op-ed from Gómez in which he asked the Obama administration to delete the DACA database. He knew Trump would use it as a weapon.

On September 5, Attorney General Jeff Sessions announced the end of the Consideration of Deferred Action for Childhood Arrivals (DACA). In six months, the program will end and 800,000 dreamers and millions more potential dreamers will face detention and deportation. Worse, Washington has an amazing tool to help it target and deport DACA recipients—a US Customs and Immigration Services (USCIS) database filled with the personal details of both DACA recipients and applicants, who volunteered this information under the Obama administration in order to gain a kind-of legal status.

To receive DACA status, undocumented immigrants had to pay more than $400 and fill out lengthy forms about themselves and their families. They went down to a government office and let officials fingerprint them and take their picture. Basically, the Trump administration has everything it needs to find and deport the dreamers. The very tool Washington used to shield them may soon become a weapon against them.

USCIS had promised to wall off the data from other federal agencies, but that changed when Trump took office. "Information provided to USCIS in DACA requests will not be proactively provided to ICE and CBP for the purpose of immigration enforcement proceedings, unless the requestor meets the criteria for the issuance of a Notice To Appear or a referral to ICE under the criteria set forth in USCIS' Notice to Appear guidance," DHS said in a prepared statement.

Gómez saw all of this coming and he warned the U.S. about it in the days after Trump's election. Motherboard caught up to him on the phone after Sessions announced the end of DACA.

MOTHERBOARD: You Warned about this. How are you feeling?

Gómez: Even though this is something I saw coming, I'm still outraged by it and saddened by the fact that they are ending the program. I didn't want my fears to be confirmed...but it's something that a lot of young undocumented immigrants thought about before applying.

The fear of the presidency changing and this information being used for other purposes led to many undocumented people who were eligible for DACA to not apply in the first place. So those people may feel like they made the right choice.

You're a former dreamer. What's your background?

I came from Argentina when I was two and a half, almost three years old. I grew up in Miami, Florida. I went to Miami Dade College for my first two years. I was in the honors program there that allowed me to go to school. I had to pay the international student tuition while I was there.

The year I graduated they started giving in-state tuition to students with DACA. Once I got DACA, I was able to transfer to American University in Washington, D.C. After I finished up there I started working for Define American.

You understood the risks of turning over your private info to the government. Why do it?

When you're completely undocumented, you're already risking everything. You get stopped by an officer for any reason [and] you can get detained and deported. I couldn't get a job anywhere legally. I couldn't get a driver's license. I couldn't leave the state unless someone drove me.

I knew that I had to live my life and go to the college I wanted to, not just the colleges that were a bus ride from my house. I needed to work and drive and do all the things that everyone else can. At that point I had already come out, publicly, as undocumented. We were put in a place where we had to make a decision between being secure and not giving over our info...or taking some risks and getting some privileges.

What's that process like? What info did you give?

Part of what you pay for—which is now $495, it was $465 when I had DACA—part of that fee is for biometrics. So, you go and get your picture taken and all of your fingerprints taken. The actual written information is your income level, everywhere you've lived in the U.S., how you entered the U.S., if you have documentation on that … it's more or less everything. The more information you provide, the better your case is.

I have this list of hundreds of thousands—potentially over a million—undocumented immigrants, where they live and where they have lived since they've been in the country. Including, for many of them, where their family lives. Many of them don't have DACA.

Lawyers encourage you to give over as much information as you can. The government keeps track of all that. So I sent where I went to college, all my previous addresses—which included where my parents lived. You have to renew every two years and do this all over again. Everytime you move, even before you renew, every single time you move you have to fill out a form updating USCIS of your new address.

So the government always knows what your addresses is. Which is why DACA was a concern of mine. The first few months of the Trump administration we didn't know what was going to happen...I had to have contingency plans for what happens if ICE shows up. I educated other folks about what rights they have. I made plans with my wife about how she handles it if officers show up.

And it's not just the 800,000 recipients, right? ICE has information on everyone who applied an all of their family members.

Millions of Americans are part of mixed-status families. For a lot of folk, that was one of their fears. They lived with their parents who were undocumented and ineligible for any sort of path to legalization or even temporary protective status like DACA, so they didn't want to give their information out because—if ICE has their address—it's got their parents address.

So they could show up for unrelated reasons, ask everyone for their papers and detain everyone. That's happened already. Not specifically using the DACA database, but why wouldn't they use it?

Colleges can ban ICE and CBP from campus if they don't have warrants for specific students.

The problem is that it's a tempting tool that's at his disposal. Clearly Trump has been wanting to appeal more and more to his shrinking base. This DACA decision seems to be part of that. If he needs to show he's really deporting as many people as he said he would, the easiest way to do that is to say, 'Hey I have this list of hundreds of thousands—potentially over a million—undocumented immigrants, where they live and where they have lived since they've been in the country. Including, for many of them, where their family lives. Many of them don't have DACA. That list, to me, would be a temptation for the Trump administration.

When you're talking to colleges, what do you tell them they can do to resist this?

Colleges can ban ICE and CBP from campus if they don't have warrants for specific students. The school is legally allowed to say, 'Hey, you can't come here.' They're allowed to deny information about students. So if ICE is asking for information about students, schools can say no. Those are the main things.

There's protections that aren't related necessarily to 'sanctuary' protections. DACA is tied, in a lot of states, to in-state tuition. It's tied to scholarships [dreamers] receive. By losing DACA they could potentially have their in-state tuition hiked up or they could have to pay international student tuition, which is what I paid my first two years of college.

They can lose scholarships that require DACA or a social security number. In some schools, they may not even be allowed to attend anymore. We want to make sure that, if DACA is taken away, students don't have to worry about this. Some schools have already made public statements that they'll do these things.

My Alma Mater, American University, just released a statement outlining the things that they'll do to protect dreamers. They won't give away students identification and they won't allow ICE and CBP on campus, to the extent they're allowed to by law. The other thing they can do is they have campus police. They can refrain from using campus police for federal enforcement (Here's where you can find petitions at Define American College Chapters.)

What about other forms of legal resistance?

I think a lot of folks are really focused on protecting people. There were some senators and members of congress who were trying to push Obama to erase the database. But I don't know can be done right now besides letting people know that this is happening. The push would have to be to get the Trump administration to erase the database themselves. Which I don't see happening.

If local enforcement is providing sanctuary in the same way that campuses are—not using local enforcement for federal enforcement—which is a conservative point of view. We shouldn't use our local and state police for to do the work of the federal government. If local and state governments say they won't hand over their citizens information, that would be hugely helpful.

There's widespread support for folks with DACA and undocumented immigrants in general in this country. I think if folks get mobilized it will help. People are starting to see why there was so much urgency in the sanctuary movement. We saw this coming and so we were preparing for exactly this situation.