WASHINGTON — President Donald Trump on Wednesday will sign the Laken Riley Act into law as his administration’s first piece of legislation. It mandates the detention and potential deportation of people in the U.S. illegally who are accused of theft and violent crimes before they’ve actually been convicted.

The measure swiftly passed the Republican-controlled Congress with some Democratic support, despite immigrants rights advocates decrying it as extreme enough to possibly trigger mass roundups of people for offenses as minor as shoplifting.

Trump has made a promised crackdown on illegal immigration unprecedented in the nation’s history a centerpiece of his political career, however, and is now suggesting the law might only be the beginning.

“This shows the potential for additional enforcement bills that will help us crack down on criminal aliens and totally restore the rule of law in our country,” the president said at a conference of House Republicans held at his Doral golf club in Florida.

The law is named for Laken Riley, a 22-year-old Georgia nursing student who went out for a run in February 2024 and was killed by Jose Antonio Ibarra, a Venezuelan national in the U.S. illegally. Ibarra was found guilty in November and sentenced to life without parole.

“To have a bill of such importance named after her is a great, a great tribute,” Trump said. “This new form of crime, criminal, illegal aliens, it’s — it’s massive, the numbers are massive and you add that to the crime we already had.”

The speed at which the act cleared Congress — and the fact that Trump is preparing to triumphantly sign it at the White House surrounded by lawmakers and other supportive, invited guests just nine days after taking office — adds to its potent political symbolism for conservatives. Critics say the measure is using a tragedy to effectively unleash chaos and cruelty while doing little to fight crime or fix an antiquated federal immigration system that hasn’t been overhauled in decades.

Under the Laken Riley Act, federal officials are required to detain any immigrant arrested or charged with crimes like theft or assaulting a police officer, or offenses that injure or kill someone. It further gives legal standing to state attorneys general to sue the U.S. government for harm caused by federal immigration decisions — potentially allowing the leaders of conservative states to help dictate immigration policy set by Washington.

Ibarra had been arrested for illegal entry in September 2022 near El Paso, Texas, amid an unprecedented surge in migration, and released to pursue his case in immigration court. Federal officials say he was arrested by New York police in August 2023 for child endangerment and released. Police say he was also suspected of theft in Georgia in October 2023 — all of which occurred before Riley’s killing.

“This is the right thing to do,” House Speaker Mike Johnson, R-La., said after the act cleared the House. “It’s always good when the right thing is also the popular thing.”

Some Democrats, however, have questioned the act’s constitutionality. Immigrant advocates are bracing for mass detentions that they say will trigger subsequent, costly construction of immigration lockup facilities to house the people arrested.

“They don’t just get to celebrate. They get to use this for their mass deportation agenda,” Naureen Shah, deputy director of government affairs in the equality division of the American Civil Liberties Union, said of the act’s supporters.

The ALCU says the act can allow people to be “mandatorily locked up — potentially for years — because at some point in their lives, perhaps decades ago, they were accused of nonviolent offenses.”

Hannah Flamm, interim senior director of policy at the International Refugee Assistance Project, said the law violates immigrants’ basic rights by allowing for detaining people who haven’t been charged with, much less convicted of, wrongdoing. Still, she said, “The latent fear from the election cycle of looking soft on crime snowballed into aiding and abetting Trump’s total conflation of immigration with crime.”

Flamm said the act is likely to be challenged in court on its parameters directing mandatory detentions, as well as its granting legal standing to state attorneys general in immigration cases and policy. But she also predicted that a need to pay for more immigration detention centers will give advocates a chance to challenge how federal funds are appropriated to cover those costs.

“I think it is pivotal to understand: This bill, framed as connected to a tragic death, is pretext to fortify a mass deportation system,” Flamm said.

The signing of the Laken Riley Act follows a flurry of first-week executive orders by Trump that are designed to better seal off the U.S.-Mexico border and eventually move to deport millions of immigrants without permanent U.S. legal status. The new administration has also canceled refugee resettlement and says it may attempt to prosecute local law enforcement officials who do not enforce his new immigration policies.

“We’re tracking down the illegal alien criminals and we’re detaining them and we’re throwing them the hell out of our country,” Trump said. “We have no apologies, and we’re moving forward very fast.”