Members of Arkansas Democracy Coalition and other groups rally at the Arkansas state Capitol in May calling for a constitutional amendment to overturn the 2010 Citizens United ruling. (Danny Johnston/Associated Press)

Bruce Ackerman and Ian Ayres are professors of law at Yale Law School and authors of “Voting with Dollars: A New Paradigm for Campaign Finance.”

In Seattle, voters just sent a message to the nation. In adopting a sweeping campaign finance reform, they have shown that recent Supreme Court decisions don’t block decisive change. With appropriate revisions, the “Seattle idea” can be taken national and serve as a litmus test of political seriousness for presidential candidates, who no longer should be allowed to pretend that only minor reforms are possible until the court reverses its decision in Citizens United. The time for action is now.

The “Seattle idea” is straightforward: Provide each registered voter with a “democracy voucher” of $100 that he or she can spend for only one purpose — to support their favorite candidates for municipal office. One person, one vote, one voucher: This is the formula for reclaiming democracy in the United States.

With the approval of Seattle’s Initiative 122, candidates will remain free to rely exclusively on old-fashioned campaign contributions to fund their campaigns. But if they want to compete for the new democracy dollars, they must agree to an overall expenditure limit.

The challenge is to transform Seattle’s approach into a plausible national program. Suppose, for example, that federal legislation provided every registered voter a special credit-card account containing $50 during presidential years, and lesser amounts during off years, funded by tax revenue. Account-holders could send their democracy dollars to a government Web site that would credit the money to their favored candidates and political organizations. About 130 million Americans went to the polls in 2012. If they all spent their democracy dollars, they would have injected about $6.5 billion into the campaigns. While the Trumps and Bloombergs of the world might choose to rely on their own mega-billions, the attractions of citizen financing would prove irresistible for mere millionaire candidates.

The voluntary character of candidate participation is crucial to the constitutionality of the program. The Roberts court is sure to invalidate any effort to force candidates into a public funding system. It has even struck down funding statutes that increase the subsidy available to participants when their opponents raise excessive sums from big givers. Under the federal initiative we advocate, the sum provided in each voucher would remain the same even if one of the candidates in a race raised a billion in private funds. With this proviso, the reform legislation would fall squarely within the bounds of earlier decisions, never challenged by the court, that uphold spending limits on candidates who choose to accept public financing.

Suppose, however, that special interests successfully blocked spending limits at the national level and participants were free to continue raising unlimited private funds even as they took in democracy dollars. Even in this worst-case scenario, citizen contributions of $6.5 billion would greatly dilute the power of private money. In 2012, $7 billion was spent by all federal candidates and their nominally “independent” supporters; while this sum may well increase during future electoral cycles, a substantial democracy dollar initiative would serve as a powerful counterweight.

The “Seattle idea” can transform the very nature of the campaign. Candidates would no longer spend most of their time auditioning before big-money audiences. Fundraising would become a community affair — a box lunch for 100 could gross 5,000 democracy dollars! These outreach efforts would provoke tens of millions of dinner-table conversations: Who should get our democracy dollars? Who is really concerned about America and its future?

This dynamic would not only generate a renewed sense of citizenship, it would also reframe the central issues put before voters. As political scientists Martin Gilens and Benjamin I. Page have shown, a substantial shift in the opinions of median-income voters has no impact on a vast array of 1,700 issues considered by Congress. But a comparable shift in the views of the top 10 percent almost triples the chances of congressional action.

More conventional approaches to campaign finance reform fail to confront these stark realities. While ordinary Americans would contribute their vouchers, they have better things to do with their real money — such as spend it on rent and food and clothes for their kids. That’s why we shouldn’t be satisfied with initiatives — such as the one adopted in New York City — under which the public matches small private contributions 6 for 1. This program has generated an increase in small donations, but the share coming from average citizens remains insubstantial. Only democracy dollars can provide the overwhelming majority with a real say in American politics.