Being a loser on Election Day in San Francisco no longer means one has lost the race.

The city has become the first to adopt instant runoffs for nearly all municipal races, a move that will eliminate costly, conditional runoffs and give underdogs a political boost, supporters say.

Opponents call the new plan undemocratic and confusing.

Under current law, if no candidate for a city office gets more than 50 percent of the vote, a runoff is held weeks or months later between the top two vote getters. The cost to taxpayers is about $1.6 million each election.

The new instant system, which won approval from city voters on March 5, would avoid this second round of balloting by allowing the voters to rank candidates as their first, second and third choice. Those preferences would be used to pick a winner.

Under the system, when no candidate gets 50 percent, the candidate with the least number of votes is eliminated. Election officials will then look to the second choice of voters who elected the eliminated candidate. The second choice votes are then added to the tallies of the remaining candidates.

If this does not create a majority winner, the process is repeated. The third choices of voters whose first and second choices have been eliminated are applied to the remaining candidates, and so on, until someone gets a majority.

Opponents say the new system goes against the principle of "one man, one vote."

"I see it as undemocratic. There may be challenges made in court," said Chris Bowman, a Republican political consultant and former member of the San Francisco citizens advisory committee on elections.

Proponents say the new system will open the political process to more outsiders and save money, since "it will benefit the city in terms of the millions of dollars it will save and also the wear and tear on the department of elections," said Mark Leno, a member of the city Board of Supervisors.

"It will encourage greater voter participation," Leno added.

The concept has been used for decades in Ireland and Australia. London recently elected its mayor using the system, and Cambridge, Mass., has been electing City Council members through instant runoffs since 1941.

The San Francisco system will be different from the one in Cambridge, where voters pick from a slate of candidates to fill multiple slots — a method that makes it possible to win with only 10 percent of the vote.

In Vermont, where the Legislature steps in and picks the winner if no one gets a majority for governor, lieutenant governor and treasurer, 51 communities recently approved non-binding resolutions in favor of instant runoffs. Alaska will have a referendum on the ballot this fall.

In San Francisco, the process will be used for most major city offices, including mayor, sheriff, treasurer, district attorney, public defender and Board of Supervisors. The counting method will kick in whenever a candidate fails to get a majority.

The city probably will not have the system in place in time for the general election in November, because the necessary software must first be approved and installed, said elections supervisor Tammy Haygood.

Supervisor Matt Gonzalez said voters and poll workers would also have to be educated about the set-up, especially after a series of vote counting foul-ups have shaken faith in the system. Last November, thousands of absentee ballots were secretly moved on Election Day and several ballot box lids were found floating in San Francisco Bay.

"Its time has come," said Board of Supervisors President Tom Ammiano, a potential candidate for mayor after Willie Brown leaves office next year because of term limits. "It allows someone with not the biggest pocketbook to be a player."

That includes marginal candidates popular in San Francisco, like former Green Party presidential candidate, Ralph Nader, who received half as many votes as George W. Bush in 2000.

The Center for Voting and Democracy, a think tank in suburban Washington supported by Nader, funneled $50,000 of the $70,000 raised in support of the proposition, said Caleb Kleppner of the center's San Francisco chapter.

Kleppner said that while the Green Party supports the measure, he denied it was trying to secure an advantage for any particular party, a contention Bowman disputed.

"It's the Green Party's agenda. They believe it will give the Greens more leverage in controlling the outcome of the elections and controlling the government," Bowman said.

The Associated Press contributed to this report.