County councils in Prince George's and Montgomery this year have considered how best to fill council vacancies.

In Prince George's, council member Thomas Hendershot (D-New Carrollton) introduced a proposal to replace an unwieldy one-round, free-for-all election with a partisan primary and a general election.

In Montgomery, council members agreed to two-round runoffs this spring. Montgomery County also increased the requirements for candidates to get on the ballot to one percent of registered voters, out of fear that "fringe" candidates could "spoil" a special election.

The problem in our democracy, however, is not how many candidates are in a race but that the elections system does not provide any mechanism to ensure that a winning candidate receives majority support. A winning candidate in a crowded field should not come out with 18, 24 or even 40 percent of the vote. That is no kind of mandate.

Special elections are notorious for drawing large numbers of candidates -- and the more candidates, the more likely the winner will receive a sliver of the vote. This undermines how well new officeholders reflect their constituency.

Runoff elections are the right approach, but two-round runoffs are beset with problems. One, recently experienced in a Louisiana special election, is electoral fatigue: Some voters turn out for the primary but not for the general election. Turnout plummeted in the runoff election between former governor and ex-member of Congress David Treen and the lesser-known state representative David Vitter, who won.

Two-round runoffs also are costly. Prince George's officials estimate that an additional primary election costs $75,000 to $90,000. Further, two election rounds mean that candidates must raise and spend more money to run for office.

A simple reform, which Hendershot and the Prince George's County Council are studying, called instant runoff voting, can solve all these problems. This system operates like a series of runoff elections, but requires voters to come to the poll only once; when it's coupled with voting by mail, voters don't even have to leave home.

Instant runoff voting maximizes voter turnout in one decisive election. It allows individuals to rank candidates in order of their preference: 1, 2, 3, etc. If at the end of the first tally, no candidate receives a majority of the vote, the candidate with the fewest number of first-place votes is eliminated. Votes cast for that candidate then are distributed to whomever the voters designated as their second choice.

Instant runoff voting is used for local elections in Cambridge, Mass. Overseas it is used to elect Australian members of Parliament and the Irish president, among others, and next year it will be used to elect the mayor of London.

Leaders in Prince George's and Montgomery are right to want to correct the failings of conventional special-election systems. In the interest of democracy, fiscal responsibility and campaign reform, both counties have a great opportunity to improve the electoral process for special elections by adopting instant runoff voting.

-- Eric C. Olson

is a member of the College Park City Council and deputy director of the Center for Voting and Democracy.