WASHINGTON — For the first time, the House of Representatives voted early Friday to block the federal government from enforcing its marijuana laws in states that have approved use of the drug for medical purposes.

Marijuana advocates called the vote historic.

“This is a game changer that paves the way for much more policy change to come,” said Steph Sherer, executive director of Americans For Safe Access, a group that has lobbied to end federal penalties for marijuana use.

The plan passed 219-189, with 49 Republicans teaming up with 170 Democrats to approve the measure shortly after midnight.

Rep. Dana Rohrabacher, R-Calif., attached the language as an amendment to a bill that would fund the U.S. Justice Department.

It attracted votes from conservative Republicans such as Doc Hastings of Washington state and Don Young of Alaska. In Washington state, which along with Colorado approved marijuana for recreational use in 2012, Hastings was the only Republican who voted for the measure, joining all six Democrats in the state’s delegation.

“I think it says we’re finally getting through to the Republican Party,” said Dan Riffle, director of federal policies for the Marijuana Policy Project, a pro-legalization group. “It has always confused me when people refer to this as a liberal issue. William F. Buckley and Milton Friedman were supporters of marijuana reform, and medical marijuana in particular. It’s about reducing the size and scope of government, getting government out of the doctor-patient relationship, and letting states be laboratories of democracy rather than a one-size-fits-all federal mandate.”

As a result of the vote, “Congress is officially pulling out of the war on medical marijuana patients and providers,” he said.

Tom Angell, chairman of the pro-legalization group Marijuana Majority, said the vote shows how quickly marijuana reform “has become a mainstream issue.” He said it reflected the fact that members of Congress are hearing more stories about medical uses of marijuana, including by children who suffer from seizures.

“If any political observers weren’t aware that the end of the war on marijuana is nearing, they just found out,” he said.

While Congress’ official position is that marijuana is a drug with no medical value, 22 states now allow medical marijuana, with Minnesota the latest to approve it this week when Democratic Gov. Mark Dayton signed a bill into law.

Kevin Sabet, who heads the anti-legalization group Project SAM (Smart Approaches to Marijuana) said the House vote would make it harder for the federal government to pursue illegal activity.

“No one wants to arrest cancer patients, but as it is, we know Colombian cartels are connected to selling marijuana under the guise of medicine and that marijuana is proliferating on public lands,” he said. “We’re also witnessing a train wreck in places like Colorado. This amendment hurts our ability to go after traffickers and producers, and I think a lot of members didn’t fully realize that when they voted for it.”

While marijuana advocates celebrated, the measure still faces an uncertain fate in the current Congress. No similar legislation has been introduced in the Senate.

