Maine is on the verge of joining those states giving up their rights under the Electoral College and changing election rules to award the state’s vote to the winner of the popular vote.

The state’s Senate approved the plan in a 19-16 vote on Tuesday to join a pact of 14 other states that hope to allocate all of their Electoral College votes to the winner of the popular vote, according to WMTW ABC 8.

The plan will have to go back to the Maine House of Representatives for further consideration.

Even if Maine gives final approval of the plan, the change will not go into effect unless the other states joining the compact reach 270 electoral votes.

Maine would become the fifteenth state to join the compact. Already signed on are California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New Mexico, New York, Rhode Island, Vermont, Washington, and Washington, DC.

The entire coalition is made up of liberal states whose electoral votes went to Hillary Clinton in 2016. Maine, however, split its votes in 2016, with three going to Clinton and one to President Trump.

Winning the White House despite losing the popular vote is hardly unheard of. Five presidents have done so: John Quincy Adams (1824), Rutherford B. Hayes (1876), Benjamin Harrison (1888), George W. Bush (2000), and Donald Trump (2016).

While the popular vote movement is almost exclusively a liberal effort, the idea has found some few conservatives who support it. For instance, former Republican National Committee (RNC) chairman Michael Steele and former Michigan GOP chairman Saul Anuzis have both endorsed the idea. However, the conservative Eagle Forum has excoriated the idea.

Follow Warner Todd Huston on Twitter @warnerthuston.