Mike Blake / Reuters Former New York City Mayor Mike Bloomberg speaks at the ninth Democratic presidential debate at the Paris Theater in Las Vegas, Nevada on Feb. 19.

Former New York City Mayor Michael Bloomberg, a multibillionaire media and financial mogul, has given his presidential campaign $463 million since it launched in November, roughly $180 million more than every small dollar donor in the United States has given to the other 28 candidates who have sought the Democratic presidential nomination this cycle.

Bloomberg has used this money, the totals of which were revealed in Federal Election Commission reports filed Thursday, to essentially drown out the preferences of the millions of Americans who have donated to other candidates. He has spent his money in ways both extravagant — free sushi for his staff and catered spreads for his supporters — and practical, by airing hundreds of millions of dollars’ worth of television and digital ads. This ad blitz boosted his poll numbers even as he declined to compete in the traditionally crucial early states of Iowa and New Hampshire, and even as elements of his record would typically repel Democratic voters. It made him a top-tier contender for the nomination, though a wretched performance at Wednesday night’s debate in Las Vegas may end his hopes of a primary victory.

But Bloomberg’s relative success highlights a danger for progressives who are hoping to upend traditional campaign finance practices, and an awkward reality for Democrats who have celebrated the boom in small-donor giving since the election of President Donald Trump: Under the existing campaign finance rules unleashed by the Supreme Court’s Citizens United decision, small-dollar donors simply can’t match billionaires. (Traditionally, any donor who gives under $200 to a campaign is considered a small donor.)

Since Vermont Sen. Bernie Sanders’s unprecedented success with small-dollar donors in 2016, progressives have hoped that a revolution in campaign finance practices could lead to a bolder, more left-leaning Democratic Party. Small-dollar donors could replace traditional giving from wealthy donors, freeing Democrats to pursue bolder policies that make the traditional donor class uncomfortable, such as “Medicare for All” and a wealth surtax. Sanders’s campaign often boasts about how many donations it receives from public school teachers and Walmart employees, while Massachusetts Sen. Elizabeth Warren has said ditching high-dollar fundraising has allowed her to embrace more liberal policy plans.

“I’m not running a campaign that’s shaped by a bunch of consultants with plans that are designed not to offend big donors,” Warren has said as part of her stump speech. “I passed that stop sign a long time ago.”

“There is a reason why these people are putting huge amounts of money into our political system,” Sanders said of wealthy donors during a debate with then-presidential hopeful Hillary Clinton in 2016. “And in my view, it is undermining American democracy and it is allowing Congress to represent wealthy campaign contributors and not the working families of this country.”

Sanders and Warren have led the rest of the Democratic field in fundraising despite shunning traditional high-dollar fundraising tactics and bringing in most of their money online in chunks of $30 or less. But while collecting enough small donations to match the federal maximum donation of $2,800 has been relatively easy, neither candidate has come close to matching Bloomberg’s level of fundraising.

It’s easy to brush off these concerns — after all, Sanders is the front-runner for the nomination at the moment despite being massively outspent by Bloomberg. But presidential races, which are intensely covered by the media, are unique. In down-ballot contests, paid advertising is far more influential ― just look at how Bloomberg-funded ads helped Democrats pick up additional House seats in 2018.

And a recent report from the Brennan Center for Justice makes it clear just how much big donors are lapping small donors in those races. In 2018, small-dollar giving did spike more than 50% compared to the previous midterm election in 2014. But the largest gifts ― those from donors who gave $100,000 or more to political committees ― spiked even more.

“There are fewer than 3,500 of these $100,000 donors — who are each giving well over the median American household’s annual income,” Ian Vandewalker, senior counsel for the Democracy Program at the Brennan Center, wrote in the report. “They gave more money than at least 7 million donors of $200 or less.”

In 2010, the first midterm election year held after the Citizens United decision, donors giving more than $1 million made up about 1% of all federal election giving. In 2014, that number jumped to 10%, according to the Brennan Center. By 2018, it was more than 20%.

The Brennan Center report reaches a stark and depressing conclusion: “Small donors — even in the millions — can’t compete with the influence bought by unlimited giving from wealthy interests.”

There are ways to change this: Basically every major Democratic candidate backs significant reforms to the campaign finance system. Former Vice President Joe Biden has backed public campaign financing since the 1970s. Warren has proposed matching small-dollar donations with public funds, and both she and former South Bend, Indiana, Mayor Pete Buttigieg have promised to make pushing a massive democracy reform package their first act as president.

Bloomberg, so far, has been silent on the issue.