LOS ANGELES — Sheriffs across the nation are openly rejecting the Obama administration policy of holding noncitizens who are accused or convicted of crimes for extra time, which for years has enabled the federal government to begin deportation proceedings for thousands of immigrants.
The local decisions are limiting the Obama administration’s ability to enforce immigration laws and could significantly decrease the number of immigrants deported each year.
The phenomenon started this spring, after a federal judge in Oregon ruled that a sheriff had violated an immigrant woman’s civil rights by holding her in the county jail solely at the request of federal agents.
Almost immediately, sheriffs across the state started refusing to honor the policy, which asks them to hold undocumented inmates without probable cause for a criminal violation, a process known as a detainer.
Now, dozens of sheriffs are doing the same: releasing noncitizen offenders who have served their time rather than holding them longer on behalf of the Department of Homeland Security.
The immigration detainers were introduced nearly a decade ago, but the use of them increased when President Obama took office, in large part to emphasize the kind of enforcement efforts the administration called its priority: capturing criminals who were living here illegally and likely to commit more crimes.
In some places, including Massachusetts, state officials resisted almost immediately, seeing the policy as a dragnet that would encourage racial profiling and unfairly lead to deportation of people who had not committed major crimes.
Mayor Martin J. Walsh of Boston has decided that police should not detain illegal immigrants for possible deportation unless they were convicted of a serious crime.
The most recent wave of resistance is driven by sheriffs who are wary of being sued.
For years, the administration has asked sheriffs to hold the detainees for up to 48 hours after they were scheduled for release, giving Immigration and Customs Enforcement extra time to investigate whether they could be deported for immigration violations.
But the sheriffs who are now resisting — many of them in California, and some in Minnesota, Kansas, and Washington — say the court ruling in Oregon forces their hand, because they cannot risk doing something a US magistrate judge has found unconstitutional.
“When a judge says something is in violation of the Fourth Amendment, I am not going to just keep doing it,” said Sheriff William Gore of San Diego.
The decision, said Gore, has nothing to do with his own position on immigration, but rather with the predicament that Washington seems to have left him with.“We need them to figure this out,” he said. “They can’t just rely on us to do it for them.”
The Obama administration expanded the detainer program as a way to strengthen immigration enforcement and create a uniform policy for local police and sheriffs’ departments.
The backlash is creating the kind of patchwork system the policy was meant to avoid. Last month, California’s attorney general, Kamala D. Harris, published an advisory memo telling law enforcement officials that departments that abide by the detainer requests could be vulnerable to lawsuits.
The local changes are likely to increase pressure on Obama, who is already facing criticism from both sides of the immigration debate. Amid the influx of Central American immigrants along the Texas border, Republicans in Congress are increasingly lashing out against what they see as lax enforcement, even as immigration reform advocates intensify their efforts to persuade the administration to ease deportations.