House lawmakers will question the mayors of four of the country's largest cities Wednesday about their sanctuary city protections, which restrict local officials in helping enforce federal immigration law.
The Republicans who lead the House Oversight and Government Reform Committee have long criticized such laws, as has President Donald Trump, a Republican who returned to the White House in January promising to deport more unauthorized immigrants than his predecessors.
The committee has invited the mayors of Boston, Chicago, Denver, and New York City, all Democrats, to explain and defend the laws during a televised hearing at 10 a.m. ET.
Some mayors have defended the laws as making all their residents safer.
However, New York Mayor Eric Adams, who is trying to get Trump to dismiss a federal criminal indictment charging him with corruption, has said he wants the city's laws weakened to allow cooperation with the federal government's deportation efforts where a migrant has been only accused, but not convicted, of a serious crime.
He also wants to allow federal immigration agents back on Rikers Island, the city's main jail complex. New York City Council members have said they will not weaken the law.
State and municipal officials have said the U.S. Constitution's 10th Amendment prevents the U.S. government from compelling local officials to enforce federal law.
In announcing Wednesday's hearing, Republicans released a video of news reports of immigrants being arrested for violent crimes cut with clips of Democrat mayors defending local laws that protect due process and other rights for migrants.
Committee Chairman James Comer, R-Ky., wrote in his invitation to the mayors the local laws were "misguided and obstructionist policies" that "hinder the ability of federal law enforcement officers to effectuate safe arrests and remove dangerous criminals from American communities, making Americans less safe."
The specifics of sanctuary laws vary from city to city, but are generally intended to afford migrants similar due-process rights as those of citizens, and to encourage people to speak with local police if they are victims of or witnesses to a crime, without fear their illegal status will be investigated.
In most cases, sanctuary laws forbid local officials from arresting or detaining a person the federal government suspects of violating its civil immigration code unless a judge has issued an arrest warrant.
Even in sanctuary cities, U.S. Immigration and Customs Enforcement officials are free to arrest people they have cause to believe are living in the U.S. without authorization, typically a civil, not criminal, violation.
ICE has a major field office in lower Manhattan, and its officers arrest hundreds of migrants across New York City each year under both Republican and Democratic presidents.
The U.S. Department of Homeland Security can deport non-citizens once an immigration judge has issued a final order of removal.
The main point of contention has been over how some cities handle what ICE calls detainer requests. ICE officials routinely ask local prison, jail or police officials to continue to detain a migrant who was free to leave custody: they have posted bail, a judge has ordered their release, or they have completed a prison sentence.
The majority of these requests come without a judge's warrant, which some federal judges have ruled violates the U.S. Constitution's Fourth Amendment prohibition on unreasonable searches and seizures.
In New York City and elsewhere, local officials must ignore the requests unless they come with a judge's warrant and the migrant has been convicted of a violent felony. ICE officials must instead arrest the migrant independently, typically at their home or place of work, which they say makes their job more difficult and dangerous.
Trump deported 37,660 people during his first month in office, according to U.S. Department of Homeland Security data, far less than the monthly average of 57,000 removals and returns in the last full year of his predecessor Joe Biden's administration.