For months, immigration advocates have been planning for the possibility of Donald Trump’s return to the White House. Now, their worst fears have arrived.

Immigrants’ rights groups have spent the last year preparing for a second Trump term and an overhaul of the nation’s immigration system, analyzing Trump’s proposals, drafting legal briefs, coordinating messaging and organizing aid for immigrants and asylum seekers. They responded to Trump’s victory with alarm and vowed to put up a fight, setting the stage for four more years of contentious court battles with his administration.

Some are already preparing to push current leadership at the Department of Homeland Security to take steps to stymie the incoming Trump team, particularly on immigrant detention and the use of AI in enforcement.

“We should expect to see the devastation of immigrant communities all over the country. We should expect to see family separation,” said Kica Matos, the president of the National Immigration Law Center. “It is entirely possible that he will try to use the military to carry out deportations, so that means that Americans all over the country will see the military engaging in enforcement against civilian populations, which is horrifying.”

Trump, after winning a historic victory on a platform of turbo-charged immigration enforcement, has said he will conduct mass deportations at a scale never before seen. Immigrant advocates have warned this would be expensive and inhumane, separating families and wrecking communities. The president-elect has also vowed to build huge detention camps, hire thousands more border agents, funnel military spending toward border security and invoke the Alien Enemies Act of 1798 to expel suspected members of drug cartels and criminal gangs without court hearings.

He has also said he would end “catch-and-release” — allowing migrants to remain free, often with monitoring, while they await immigration court hearings — and restore a policy from his first term requiring asylum seekers to remain in Mexico while their cases are processed. And he has dodged questions about whether he would try to bring back family separation.

Advocates are preparing for an exhausting battle reminiscent of his first four years in office. Immigration and civil rights groups challenged many of his policies in court, with judges blocking Remain in Mexico and his executive order banning travel from seven Muslim-majority countries and family separation, among other policies. Now, groups say they’re better prepared than they were in 2016 — ready to move quickly depending on how the president-elect proceeds.

“We are much more sophisticated and organized in realizing that everybody should look at where their strengths are, where their service capacity is,” said Greg Chen, senior director of government relations for the American Immigration Lawyers Association.

One challenge: funding. These legal battles range from high-stakes policy fights to representation of individual immigrants facing deportation. Archi Pyati of the Tahirih Justice Center, which advocates for people fleeing gender-based violence and forced marriage, noted that heightened immigration enforcement means more legal fights — which can be expensive.

“We know it’s going to take a lot of smart lawyers to hold back the worst human rights violations that may be coming, to protect the legal structures that allow immigrants and refugees to find safety in the U.S. and to exercise their basic human rights on the domestic and international stage, and we are preparing ourselves for the legal battles that lay ahead,” she said. “We need resources for sure.”

Advocates are bracing for a firehose of early executive actions, followed by more detailed agency initiatives in the first 100 days — an expected echo of Trump’s first term. Jason Miller, Trump’s senior adviser, said on Wednesday that the president-elect’s first moves would be to reinstate Trump-era border policies.

Advocates’ anxieties are heightened for a number of reasons. They fear how the Supreme Court’s composition could benefit Trump. And they’re watching the House results closely, anxious that a trifecta could make it easier for the president-elect to fund his proposals in Congress. And they fear that without concerns about reelection, Trump won’t worry about political consequences.

“It’s his second term. Ostensibly they’re not worried about re-elect, so now’s the time to get all the crazy stuff done,” said Hassan Ahmad, a northern Virginia immigration lawyer and advocate.

They also worry that the immigration hawks surrounding Trump will be better at hiring officials who will quickly roll out the president’s policies.

“The Trump administration’s incompetence during the first term was the silver lining that allowed many of his policies to be stopped,” Ahmad said. “I’m not expecting that to happen nearly as much during his second term. They eventually figured it out — how to program the machine.”

But immigrants’ rights groups have their own counter-programming. Omar Jadwat, director of the ACLU Immigrants’ Rights Project, said his organization has spent months preparing legal challenges to Trump’s anticipated immigration policies. Other groups, including Just Futures Law and Detention Watch Network, will urge DHS Secretary Alejandro Mayorkas to take action to blunt Trump’s agenda.

Silky Shah, Detention Watch’s executive director, said her organization will urge DHS to cancel efforts to open new detention centers. Even though the Trump administration will likely seek to expand the capacity of detention centers to speed up deportations, the Biden administration could still slow that process by reversing course on any current expansion efforts, she said. Her group has already urged DHS to withdraw requests for proposals on expanded detention, she said, and they will underscore the urgency of that request in the coming weeks. Her group is also urging DHS to quickly shut down other facilities.

Mayorkas’ team can also expect pressure regarding the department’s use of AI and biometric information to enforce immigration laws. Paromita Shah, the co-founder and executive director of Just Futures Law, said her group has long raised concerns about how the department is planning to use AI to vet people seeking visas and for translation services.

“There are things this administration can do to ensure that these technologies aren’t abused,” she said — adding her group will push DHS to move fast.