“We will no longer violate anybody’s constitutional rights, I can guarantee that,” Sheriff Bettencourt said.

The Oregon decision was the latest of several federal rulings this year that raised doubts about the constitutionality of detainers that federal authorities have routinely issued to state and local police, asking them to hold foreigners they had arrested for additional time.

The detainers, which are issued by Immigration and Customs Enforcement, known as ICE, request that immigrants be held for up to 48 hours so their legal status can be investigated.

The shift by sheriffs in Oregon adds to growing resistance nationwide to the expansion under the Obama administration of the local reach of federal immigration enforcement. The effort has helped produce about two million deportations under President Obama, more than any other president.