ANNAPOLIS, Md. (AP) -- Maryland is poised to become the first state to approve giving its electoral votes for president to the winner of the national popular vote, rather than to the candidate chosen by state voters.

The plan, passed Monday by the state House, would take effect only if states representing a majority of the nation's 538 electoral votes adopted the same change.

Some states are considering the move as a way to avoid a scenario in which a candidate wins the national popular vote but loses in the Electoral College, as Democrat Al Gore lost to George W. Bush in 2000.

Supporters of the Maryland bill said the state, which has 10 electoral votes, gets passed over by presidential candidates who head to larger battleground states. Opponents say the change is unnecessary and constitutionally questionable.

The final vote in the Democrat-controlled House of Delegates was 85-54, with only one Republican endorsing it. The Senate has already passed the bill, and Gov. Martin O'Malley, a Democrat, plans to sign it, said spokesman Rick Abbruzzese.

Delegate Jon Cardin argued that the measure would make Maryland more relevant in the presidential campaign.

"If you want Florida and Ohio to continue to have all the attention, all the money and all the interaction with presidential candidates, and have us be overlooked, then don't vote for this bill," said Cardin, a Democrat.

But House Republican Leader Anthony O'Donnell called on lawmakers to reject the measure, which he argued would allow people outside Maryland to dictate the voters' choice and turn the state away from constitutional safeguards designed to protect smaller states.

"In fact, the citizens of Maryland could vote overwhelmingly, 100 percent, for one candidate, and yet the electors of Maryland -- the 10 electoral votes -- could go for another candidate," O'Donnell said.

Under the present system, voters support slates of electors, who then meet to choose the president. The Electoral College has 538 members, and the winning candidate needs at least 270 votes.

National Popular Vote, a group that supports the change, says bills have been introduced in 22 states. The Arkansas House and Hawaii and Colorado senates have voted for the change. North Dakota and Montana voted against it this year.

California lawmakers adopted the measure last year, but Republican Gov. Arnold Schwarzenegger vetoed it.

"This opens the door to a national popular vote for president, which is something that people have wanted for a long time," Ryan O'Donnell, a spokesman for the group, said of the Maryland bill.