JUST A handful of jurisdictions across the country have embraced public financing systems for local elections, aiming to use taxpayers’ money to offset the clout of special-interest cash in campaigns and to promote competitive races. Montgomery County is considering legislation that would make it the first in the Washington area to adopt such a system. The bill’s details may shift as the all-Democratic County Council grapples with it, but the concept deserves support.

The measure, proposed by Council member Phil Andrews (who is running for county executive), would begin with the 2018 elections for county executive and County Council. It would be voluntary; any candidate would be free to decline public matching funds and continue raking in donations the old-fashioned way — from developers and unions, which play an outsize role in Montgomery’s elections, as well as from other groups and individuals.

Candidates who opt in to the system would be rewarded with public matching funds if they are able to cultivate a significant base of grass-roots contributors within the county. They would have to meet a certain threshold in fundraising to demonstrate their candidacies are more than quixotic: at least $40,000 for county executive, $20,000 for at-large council seats and $10,000 for district council seats.

To qualify for public funds, they could accept donations only from individuals (not political action committees or other groups) up to a maximum of $150 per county donor, which would then be matched according to a complex formula that rewards smaller contributions the most. A council candidate who could raise $50 each from 625 donors, for a total of $31,250, would receive $125,000 in matching funds, the maximum for a district seat. (As the legislation stands, the matching limit for an at-large council seat would be $250,000 and $750,000 for county executive.) Beyond the limits on public matching funds, candidates would be free to continue raising money, but not more than $150 per donor.

The bill in Montgomery is the upshot of the state’s campaign finance reform law, enacted last year, which gave localities the option of setting up public financing mechanisms. About half the states, including Maryland, have experimented with varying methods of public financing of campaigns. To be effective, a system must offer enough money to enable candidates who opt in to run a competitive race, but not so much that taxpayers feel bilked into footing the bills for lavish campaign spending.

Mr. Andrews’s proposal seems to strike the right balance. It offers a decent chance of blunting the influence of unions, developers and other special interests to some degree; increasing the number of donors by giving candidates the incentive to seek small, in-county contributions; and encouraging motivated non-incumbents to run for office. Those would be good outcomes for a system that would cost county taxpayers about $3 million a year.

Mr. Andrews’s colleagues on the council have lined up behind the bill . Possibly, they see the measure as providing them with a break from the tyranny of non-stop pandering and election year fundraising. Amen to that.