How Much Damage Can Trump Actually Do to Immigration Policy?

On Tuesday evening, Greisa Martinez sat huddled with 40 friends around a TV to cheer Hillary Clinton's victory. But that night, Martinez—a 28-year-old Mexican immigrant who moved to the United States at age seven—was shattered by Donald Trump's win in the presidential race.

Martinez braced for the worst: Trump, who vowed to "immediately terminate" the deportation relief President Obama granted to 800,000 young people who came to the US as children, could strip her work permit and possibly even deport her.

"I am concerned, I am scared," Martinez told me. "The impact of this will be immense."

Ending deportation relief is just the tip of the iceberg: Trump shaped his campaign with ideas like building a border wall, banning Muslims from the country, and kicking out all 11 million undocumented residents with a deportation force, to name a few. But now that he's president-elect of the nation built by immigrants, what does he actually have the power to do? We looked at how a Trump administration—backed by a Republican Congress—is capable of changing immigration in America.

One of the likeliest things that Trump can and will do is to end Obama's Deferred Action for Childhood Arrivals, or DACA, which gave deportation relief and work permits to undocumented youth who arrived in the country under age 16, went to school, and complied with the laws.

"Trump does have the power to reverse this on his own, but one unanswered question is if he will then terminate work permits people already received through Obama's executive action or say they can't get new ones," Stephen Yale-Loehr, an immigration law professor at Cornell, told me.

The repeal could put recipients like Martinez at risk because they registered with the federal government to receive benefits, and will once again be vulnerable for deportation.

"The impact would be great—over 700,000 people have received work permits and temporary relief from deportation and now all of their information in database, so it's very easy for agents to find them," Yale-Loehr told me. Even still, he said, Immigration and Customs Enforcement (ICE) "can't pick up everyone at once and Trump has said deporting criminal aliens is the top priority."

Even though Obama has deported more people than any other president, Trump suggested taking it even further, at one point promising to round up all 11 million undocumented individuals with a deportation force. More recently, Trump backed off the impossible sweep and said he'd instead deport about 5 million, targeting immigrants with criminal records and individuals who have overstayed their visas. He added that "anyone who has entered the US illegally is subject to deportation" and promised to triple the ICE force.

"He certainly pivoted to talk about a more realistic strategy later in the campaign," William Stock, President of the American Immigration Lawyers Association, told me. "He's talked about targeting the enforcement to bad dudes right away. He alleges that the government knows where these folks are but my experience is that that's not the case—if the government knew where they were, they'd deport them."

Stock pointed out that the president has power to direct enforcement priorities, but in order to expand ICE, he must request approval from Congress through the appropriations process. "Republican-controlled Congresses haven't been extremely amenable to expanding the size of the federal government, but are more inclined to with law enforcement and immigration," Stock told me.

But Yale-Loehr said the conservative Congress would almost definitely approve requested funds for ICE.

"I think they certainly want to see more criminal aliens deported, so they'll say yes," he told me.

Yale-Loehr said Trump would also likely get Congress' support to further expand immigrant detention—which is already at a record high and includes a family detention system that a federal judge deemed illegal.

Building a wall is perhaps one of the most famous promises of the Trump campaign. Since summer 2015, when he announced his candidacy, he's boasted that he would construct a 55-foot high concrete wall along the Mexican border and "have Mexico pay for that wall."

If he can't make Mexico's government pay for the wall, Trump has said he'd seize remittances sent from the US to Mexico. Stock told me Trump may try to justify that action through the Patriot Act of 2001, which allows the president to block money sent to people believed to be terrorists.

"That could be found unconstitutional if he is sued—the court would have to decide whether he was acting within or outside of the powers Congress granted him," Stock said, explaining that the remittance threat may just serve to pressure Mexico's government to pay. "But even if government of Mexico remits money to the US he can't without the approval of Congress use it to build a wall."

But Stock said he doubted Congress would approve a wall.

"There are treaty issues involved in building a wall, and there are parts of the border where it makes no sense to build a wall because there are mountains you cant climb anyway, and there are parts of the border that belong to Native American nations where Congress cant build a wall without approval of the tribes," Stock told me. "There certainly are a lot of thoughtful politicians on both sides of the aisle who think a big concrete wall is a big waste of money."

Stock called the wall a "symbolic gesture" and said Trump would more likely work with Congress to expand the current physical barrier, as well as to expand Border Patrol. Yale-Loehr also predicted Congress would increase funds to more border security.

Even though the 14th Amendment blatantly states that "all persons born or naturalized in the United States are citizens," Trump told NBC's Meet the Press last summer that he would deny citizenship to the babies of undocumented individuals.

"They've got to go," he said. "What they're doing: They're having a baby. And then all of a sudden nobody knows—the baby's here."

"He's come up with a legal theory that the 14th amendment doesn't mean what 150 years of legal scholarship shows it means, so he says we'll test it in court," Stock said.

Trump might tell the US State Department to stop issuing passports to children of the undocumented, Stock envisioned. Then those children could sue—and put Trump back in his place.

As the world faces its largest refugee crisis in recent history, Trump vowed Sunday to suspend the Syrian refugee program, and claimed he would not allow refugees from any country to be resettled in communities that did not want them.

"Here in Minnesota, you've seen firsthand the problems caused with faulty refugee vetting, with very large numbers of Somali refugees coming into your state without your knowledge, without your support or approval," Trump said on one of his final campaign stops. "How stupid are our leaders to allow this to happen?"

As president, Trump will have the total power to block refugee resettlement, according to Michelle Mittelstadt, Migration Policy Institute's Director of Communications and Public Affairs.

"The president sets the annual allocation on refugee admissions and within that number which people from which region," Mittelstadt told me. "Trump has expressed serious opposition to Syrian refugee resettlement and could stop it."

In his crusade to protect American workers, our real estate mogul-turned-president has pledged to reduce legal immigration substantially, though he hasn't specified by exactly how much. But any reduction would require Congressional approval, Mittelstadt noted—and the results are difficult to predict.

"Anybody who tells you how immigration debates are going to play out in Congress either has a crystal ball or is a fool, because immigration is one of most complex issues out there," Mittelstadt challenged. "While having a unified Congress would lend itself toward greater agreement on immigration, immigration is not just a party issue but also an idealogical one and party debates have exposed significant differences within the Republican party."

Currently, Yale-Loehr told me, about 1 million individuals are allowed to legally immigrate to the US each year—a number that Congress may hesitate to decrease, because even conservatives see economic benefits in legal migration.

But Trump could indeed stop individuals from certain countries from stepping onto US soil, whether as visitors or as immigrants, Yale-Loehr said. According to Section 212 of the Immigration and Nationality Act, the president can act without Congress to block individuals or groups of individuals from entry.

"He could suspend visas on his own, because this provision gives the president power to prevent people who are detrimental to national security from entry," Yale-Loehr explained.

Yale-Loehr stressed that it's "too early to tell" exactly what moves Trump will make, but it's likely that "overall, our immigration policy will be more nativist, protecting American workers rather than focusing on how we fit with the global economy."

Regardless of what Trump does, Greisa Martinez told me she and her fellow DACA recipients won't stop pushing for reforms.

"We'll fight for our people to remain part of the framework of our country," said Martinez. "We're not declaring defeat yet."

Follow Meredith Hoffman on Twitter.