BOSTON — Two Massachusetts Senate Republicans crossed the aisle Thursday and gave Beacon Hill Democrats a 37-3 vote on a bill that lets illegal immigrants sue federal ICE agents in state court.

The two who crossed were Minority Leader Bruce Tarr of Gloucester and Sen. Patrick O'Connor of Weymouth. Earlier in the same session, Tarr had asked the Senate to pause and let the Supreme Judicial Court rule on whether three provisions of the bill were even constitutional. The chamber wouldn't take it up. The motion failed 5-35. Tarr voted yes anyway. He had no comment.

The three no votes were Republicans Ryan Fattman, Peter Durant and Kelly Dooner.

The provision is lifted from a separate bill, S.2976, filed in February by Sen. William Brownsberger (D-Belmont). It is modeled on 42 U.S.C. § 1983, the Reconstruction-era statute that already lets people sue state and local police. Section 1983 doesn't reach federal agents. Brownsberger's text does.

"In the absence of a federal administration willing to hold its agents accountable when they depart from civil norms, states need to impose liability," Brownsberger said.

The bill also stops Massachusetts jails from honoring ICE detainers — the federal request to hold someone an extra 48 hours after their release date so ICE can pick them up.

Fattman tried to amend it to let jails honor those detainers anyway. He lost 10-29.

The practical effect: a convicted illegal immigrant who finishes a sentence at a Massachusetts house of correction walks out the front door. Not into ICE custody.

Immigrant advocates sang in the State House hallways during the eight-hour debate. The Senate gallery erupted when the vote was announced.

At a press conference after, Senate President Karen Spilka kept it sweeping.

"Massachusetts is stronger because of the immigrants who call our great state home," she said. "People deserve to live with dignity, safety and peace of mind to do their everyday life."

A reporter asked if every ICE arrest in Massachusetts is unjustified. Spilka pivoted.

"It's a pretty broad question, first of all," she said. "And again, Trump came in saying he was only going to arrest those with proven criminal records. Clearly, that's not what has happened."

More than 75 percent of immigrants detained in Massachusetts have no criminal record, said Maroni Minter, political director at the Massachusetts Immigrant & Refugee Advocacy Coalition.

The Senate's PROTECT Act also bans new or expanded 287(g) agreements between Massachusetts law enforcement and ICE. The state Department of Correction's existing agreement is preserved. Local police can't ask about immigration status. ICE is barred from courthouses, schools, daycare centers and hospitals. Out-of-state military personnel can't enter Massachusetts without the governor's approval.

Gov. Maura Healey is fully on board.

The House version, which passed 134-21 in March, didn't have the lawsuit right. Conference negotiators from both chambers will now reconcile the two bills. Under new rules, they have until the first week of January to send Healey something to sign.