Let's start with some math. There are approximately 1.5 million people in the city of Philadelphia. About 1.1 million are old enough to vote, and 980,000 are registered. As of last week, 75 percent of those, or 735,000, were registered as Democrats. That's how many people are eligible to vote in this May's Democratic primary, universally agreed to be the de facto election for Philadelphia's next mayor.

Now, recent history suggests that good turnout for a contested mayoral primary is about 50 percent (though, in 1999, only 40 percent of voters came to the polls). If we do that well this time around, the number of people who will actually vote on May 15 comes down to about 365,000. Since there are five candidates running, it's very possible that the winner will garner something like 25 percent of the vote � about 90,000 people, which is less than the population of a single City Council district.

That's right � it will take only one out of 12 Philadelphians, 8 percent of the city's voting-age population, to elect our next mayor.

This is a problem. Not only because we could end up with a mayor who doesn't have a mandate (though that's bad), but because it makes our democratic process feel staged and hollow. If the great majority of potential voters, the great majority of registered voters, and even the great majority of those who actually vote don't vote for the guy who wins, can we really be confident that our democracy is functioning?

There are three separate issues here: In addition to turnout, there's disenfranchisement and what might be called the "plurality problem."

Voter turnout is a perpetual concern that's certainly not unique to Philly. But the fact that our elections are decided in a May primary only exacerbates the problem. "It's kind of like the preseason in baseball," says Chris Sheridan, policy director for the Committee of Seventy. "People watch the World Series, they watch the Stanley Cup. People want to come for the real show." A primary is "rarely a stark choice."

Disenfranchisement refers to the fact that, unless Sam Katz is running, 25 percent of voters effectively get no say in selecting the mayor. There are more than 200,000 Republicans, Greens, Libertarians and unaffiliated voters in Philadelphia, but if a race is being decided in the Democratic primary, their votes don't matter. They could, of course, switch their registration to the dominant party � but that shouldn't be a prerequisite for meaningful electoral participation.

The plurality problem stems from Philly's one-race, winner-take-all electoral model, which raises the distinct possibility of a Ralph Nader-type spoiler, or of a split vote. Let's say, for example, that fast food becomes a major issue this spring. Chaka Fattah and Bob Brady both support McDonald's, while Michael Nutter, that maverick, goes in for Burger King. On election day, Fattah and Brady each get 25 percent of the vote, and Nutter gets the 30 percent BK minority. Evans (Wendy's) and Knox (White Castle) split the remainder. Half of voters may prefer Big Macs, but now that Nutter is mayor, we're all eating Whoppers.

If you've lived in Philly your whole life, you might think we're stuck with this electoral system. We're not.

Any changes made to Philly's election format would have to be made at the state level, because the city follows Pennsylvania's election laws. This would be hard to do, because with the exception of state Rep. Babette Joseph's plans to improve voter turnout, no one in the state is really lobbying for procedural changes. But the ideas are out there.

Around the country, municipalities are trying new forms of democracy. The most common alternative to the party primaries we're accustomed to is the nonpartisan election system. This form was popularized in the early part of the 20th century, when the Progressive movement held that local governments should focus on fixing potholes and picking up garbage, and that ideological political parties were irrelevant to these tasks. It's now used by 80 percent of the country's 100 largest cities in elections for local office; the exceptions are mostly old Eastern-Seaboard cities like Philly, New York, Washington, D.C., and Baltimore.

The elections themselves are straightforward affairs: Candidates get on the ballot by collecting signatures, and then they enter a primary. If no candidate gains a majority of the vote, the top two advance to a runoff.

Proponents argue that this system loosens the grip of local political bosses and prevents the disenfranchisement of political minorities, such as Republicans in Philly. It also addresses the plurality problem, by requiring the winner to gain a majority against a serious opponent.

But nonpartisan elections have their flaws. Detractors contend that the format disadvantages voters of lower socioeconomic status by eliminating party-based mobilization efforts; instead, candidates simply spend money to raise their name recognition. In 2003, when New York City considered a ballot measure to institute nonpartisan elections, candidate Mark Green quipped that the traditional GOTV � Get Out The Vote � would become "Go On Television." (The measure was widely viewed as an attempt to make it easier to elect Republicans, and it failed.)

Opponents also argue that affiliation with a political party conveys basic information about candidates to voters � especially important in poorly publicized races for lower offices � and that nonpartisan elections can depress voter turnout, because voters like to rally behind familiar parties.

There are other measures Philadelphia might take to address turnout concerns. Deborah Goldberg of the New York-based Brennan Center for Justice rattles off a long list of suggestions, including child care, Election Day registration and mail-in ballots. This last suggestion is, in fact, what Josephs is pursuing. As the new chair of the House State Government Committee, she is considering introducing legislation to implement "universal mail-in balloting" in Pennsylvania. She cites the model of Oregon, which had 70 percent turnout in 2006.

"I do want to raise the turnout, I do want to help reduce barriers," Josephs says. But just as nonpartisan elections do nothing to improve turnout, mail-in ballots don't address plurality and disenfranchisement issues.

There is another, relatively new idea on the electoral landscape. Instant Runoff Voting, or IRV, allows voters to rank their preferences among a field of candidates, so that if no candidate gains a majority, a runoff can take place without a new election. IRV addresses the plurality problem by requiring the winner to gain a majority of first- and second-place votes, and could well improve turnout by requiring voters to go the polls fewer times (this also saves taxpayer money).

After a recent IRV debut in Takoma Park, Md., a candidate said that, because he needed his opponents' second- and third-place votes, he campaigned differently, continuing conversations with their supporters. (Proponents have seized on this sort of comment as evidence that IRV reduces negative campaigning.)

More promising still, a new IRV system in Pierce County, Wash., incorporates political parties into a primary-free IRV system; it allows parties to award endorsements that appear on the ballot. This solves the disenfranchisement problem without eliminating the beneficial effects of parties. Robert Richie, executive director of voting-advocacy group Fairvote, describes the system as "trying to be the best of both worlds." Of course, even IRV has its detractors � people who advocate parliamentary-style proportional representation, for instance.

But that's sort of the point: Democracy is evolving. Other locales are engaging in conversations about how to make their elections as fair, as open, and as reflective of the public will as possible. It would be a shame if Philly were so subservient to Democrats that it ceased to be democratic.