By Michael Waldman

(CNN) -- US Rep. Alexandria Ocasio-Cortez's withering viral takedown of just how easily deep-pocketed donors dominate politics was like watching a prosecutor lay into a campaign finance system that has no defense.

So far, that exchange (during a hearing on House Democrats' sweeping democracy reform bill) has garnered an astounding 38 million views. It's not hard to see why. But what the viral video leaves out is that the reform bill includes a solution to curb the power of big money in politics: a voluntary public financing system for congressional races.

Here's how it would work. Small contributions would receive public matching funds, at a ratio of 6-to-1. If you give a candidate $100, for example, that becomes $700. Candidates would voluntarily limit spending. They could now fund their races by amassing small contributions, rather than those from big donors and special interests. This shift could transform politics and policymaking.

Voters long have seethed over big money's role. But the US Supreme Court has made matters far worse. Thanks to Citizens United and other rulings, billionaires (sorry, "people of means" ... well lots of means) now can fund campaigns effectively without limit, and without public disclosure. A big donor system tilts policymaking. Just one recent example: According to the Center for Public Integrity, a small group of wealthy donors suddenly poured funds into Republican campaigns and political committees as the tax cut bill was being shaped. Incumbents must spend hours a day raising funds, trooping to call centers near the Capitol that resemble nothing less than the skeezy boiler room in "Sorry to Bother You."

Public financing has long been understood to offer a better way to fund campaigns. Theodore Roosevelt first proposed it in his 1907 State of the Union. It was enacted for presidential campaigns in 1974 when the Watergate scandal revealed tales such as the Cabinet official who had to handle a briefcase crammed with $200,000 in cash from a donor. The system worked well enough for several decades. Presidents Jimmy Carter, Ronald Reagan, George H.W. Bush, Bill Clinton and George W. Bush participated. In fact, in the first five elections presidential public financing was used, three challengers unseated incumbents, a far more competitive record than nearly any congressional district.

Eventually that system fell, mostly because it simply did not provide enough money.

The issue of campaign finance receded. Sure, big money mattered, but what could anyone do about it? That notion was exploded in the 2018 election. Nearly 120 House challengers shunned corporate PAC money and vowed reform. Forty or so now serve in the freshman class, part of the most diverse Congress in history. That's a bloc as big as the "Watergate Babies" elected in 1974 who pushed House changes. This new version of reform reflects the realities of today's digital politics.

A small donor system doesn't try to end all private money in politics, a futile goal sought by earlier plans. Rather, it aims to bolster one of the most encouraging trends in political life. In 2018, individuals giving less than $200 gave $381 million to general election federal candidates.

The federal proposal is based on a successful approach used in New York City for three decades. The city's matching fund system is considered the country's best set of campaign rules. The vast majority of candidates from both parties participate. It's led to a far more diverse set of officeholders and has helped ensure that several candidates compete for each seat with enough funds. Above all it has helped curb corruption. Some smaller incidents notwithstanding, compared with recent decades, New York politicians are seldom brought down by campaign finance-related scandals or prosecutions.

Because it aims to amplify rather than squelch speech, the general constitutionality of public financing has been reaffirmed by the US Supreme Court, even in the current deregulatory era.

Today the loudest attacks come from Republicans. Why, they worry, help Democrats raise small funds? But other years, Republicans have benefited more. As Freedom Caucus chair Mark Meadows noted, he might receive millions in public funding. That's a feature, not a bug in the proposal. It would incentivize lawmakers of both parties to turn to grassroots fundraising. Critics also warn against wasting taxpayer money on politics. The plan would cost taxpayers about $1 each but would save far more by avoiding unjustified tax and regulatory policies.

Many Democrats whisper opposition, too, when caucus doors close. They don't want to bite the hand that funds them. They worry that voters might punish a plan that uses taxpayer money for politics. Since incumbents typically outraise challengers, they want to be able to build a cash wall to protect their seats.

They would ignore the rumblings of public discontent at their peril. Today voters are enthusiastic about reform. If Democrats flinch, it will be public anger that goes viral.