US PRESIDENT Donald Trump was due to sign legislation into law last night that mandates the detention and potential deportation of undocumented migrants accused of theft and violent crimes — without any need for a conviction.

The measure, known as the Laken Riley Act, swiftly passed the Republican-controlled Congress with some Democratic support, despite human rights campaigners highlighting how the law could lead to the mass rounding-up of people for minor offences such as shoplifting.

Mr Trump has made a promised crackdown on undocumented people the centrepiece of his political career. He is now suggesting that the new 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,” Mr Trump said at his Doral golf club in Florida.

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

American Civil Liberties Union deputy director of government affairs Naureen Shah warned that the Act would allow people to be “mandatorily locked up, potentially for years, because at some point in their lives, perhaps decades ago, they were accused of non-violent offences.”

International Refugee Assistance Project interim senior director of policy Hannah Flamm noted that the law violates immigrants’ basic rights by allowing the detention of people who have not been charged with, never mind convicted of, wrongdoing.

“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,” she said.

Ms Flamm said the Act was likely to be challenged in court on its parameters directing mandatory detentions, as well as its granting of legal standing to state attorneys-general in immigration cases and policy.

But she also predicted that a need to pay for more immigration detention centres 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 a pretext to fortify a mass deportation system,” Ms Flamm said.

The signing of the Laken Riley Act follows a flurry of first-week executive orders by Mr Trump that are designed to seal off the US-Mexico border and pave the way for the eventual deportation of millions of people who lack permanent US legal status.

The new administration has also cancelled refugee resettlement and says it may attempt to prosecute local law enforcement officials who do not enforce Mr Trump’s new immigration policies.