The plan is intended to circumvent court decisions that have thus far limited the role of local law enforcement in immigration. It involves a legal move regarding detainers, which are requests by Immigration and Customs Enforcement to local sheriffs or police departments to hold people who are suspected of being in the country illegally, even after they have posted bail, finished their jail sentence or otherwise resolved their criminal cases.
A handful of sanctuary cities refuse to honor detainers on ideological grounds, but a larger number of sheriffs who otherwise support the Trump administration have also turned down detainers because courts have found that they violate the Fourth Amendment.
The legal move, in which sheriffs would essentially serve as contractors for ICE, is intended to protect sheriffs from such court battles, which have sometimes resulted in costly payouts. Some legal advocates for immigrants, though, expressed doubt that courts would view it as being different from current practices.
An ICE spokeswoman said that the plan was still under review, and that a final decision had not been made.
The tactic would be a major step toward marrying local and federal law enforcement, a centerpiece of Mr. Trump’s plan to thwart illegal immigration and one that immigrant advocates have scrambled to block at every opportunity. If enough sheriffs participated, the approach could lead to many more immigration arrests, which have already risen more than 40 percent since last year.
