As a measure of democracy, one of the more encouraging statistics of the 2016 presidential race is the fact that the average contribution to the long-shot campaign of U.S. Sen. Bernie Sanders is $31.30. It would be hard to buy any politician for $31.30. That is exactly the message Sanders intends, in renouncing fat-cat, super PAC campaigning that is turning American politics into an exercise in plutocracy.

Americans of ordinary means have made 400,000 donations — about 80 percent of them were $200 or less — to Sanders. Contrast that with the appalling fact that fewer than 400 of the nation’s most-affluent families, writing six- and seven-figure checks, account for almost half of the money raised so far by both parties in the campaign, according to an analysis by the New York Times.

The Sanders campaign, whatever its fate, has at least established that small-beer donors are alive and well and enthusiastic in America. What they and democracy need as a quid pro quo is a revival of the public financing system that protected politics after the corruption of the Watergate scandals.

As things stand now, the Supreme Court’s disastrous Citizens United decision has grossly boosted the buying power of corporate and special-interest donors and made a casino frenzy of the race. The Koch brothers have proudly organized more than 400 of their wealthy allies to create a super war chest of $889 million for Republican candidates. The Jeb Bush campaign, pretending to remain at arm’s length from its supposedly independent super PACs, has raised over $100 million in big-check donations. Hillary Rodham Clinton, aiming to stay competitive, has raised more than $20 million in super PAC money, much of it from millionaires, even as she pursues small-dollar donations and vows to do something about campaign reform.

The small donors carrying the Sanders campaign are a refreshing break from the egregious money bundlers. Gone missing, however, is the post-Watergate system of matching funds that leveled the playing field for less-affluent candidates and worked well until Congress failed to update it, even though it was embraced for two decades by the major presidential candidates. George W. Bush broke with the system for more deep-pocket support in his 2000 primary victory, while President Obama was the first to turn away from it in a general election in 2008.

A worthy measure to restore public financing in presidential elections has been crafted by Reps. David Price and Chris Van Hollen and Sen. Tom Udall. Regrettably, most congressional politicians may be too engaged at their own tables in the money casino to notice as runaway money again corrupts a presidential campaign.