Montana Gov. Steve Bullock on Tuesday accused fellow Democratic presidential candidate Tom Steyer, a billionaire hedge fund manager and liberal megadonor, of buying his way into the third presidential debate.

"Tom Steyer spent nearly $10 million to buy his way onto the debate stage," Bullock tweeted. "But no matter what the @DNC says, money doesn’t vote. People do."

Bullock then released an extended statement on Steyer, whose campaign announced earlier Tuesday that he had hit the 130,000 donor requirement and was just one qualifying poll away from being assured a spot on the Sept. 12-13 debate stage in Houston.

As of Tuesday, nine candidates had qualified for the debate: former Vice President Joe Biden; Sens. Elizabeth Warren of Massachusetts, Bernie Sanders of Vermont, Cory Booker of New Jersey, Amy Klobuchar of Minnesota and Kamala Harris of California; former Texas Rep. Beto O'Rourke; South Bend, Indiana, Mayor Pete Buttigieg; and entrepreneur Andrew Yang.

"We’re kidding ourselves if we’re calling a $10 million purchase of 130,000 donors a demonstration of grassroots support," Bullock said. "It’s not serving the candidates, and it sure isn’t helping the voters who will actually decide this election."

Speaking with MSNBC's Andrea Mitchell later on Tuesday, Bullock said the Democratic National Committee's rules for qualification were "well intentioned" but "allowed a billionaire to buy a spot on the debate stage — we’re getting to the point where we’re spending money online as opposed to actually talking to voters."

Steyer, who made a late entry into the race last month after earlier this year saying he would not run for president, has gained some traction in the early primary states. His RealClearPolitics polling average has him among the top seven candidates in Iowa and New Hampshire. Nationally, he and Bullock are neck-and-neck in that polling average.

After failing to qualify for the first debate in June, Bullock hit the debate stage last month. But, like the majority of the more than 20 Democrats seeking the presidency, Bullock is at risk of not qualifying for the September debate.

Steyer's campaign manager, Heather Hargreaves, responded to Bullock on Twitter, saying the governor was "writing off" Steyer's support.

"Fewer than half of Tom's donations came from advertising," she wrote. "Writing off the support of thousands of Democratic voters who are responding to Tom’s message isn’t the way to beat Trump in 2020, no matter what you think about the DNC’s criteria."

Steyer, who has founded organizations aimed at fighting climate change and calling for President Donald Trump's impeachment, pledged to spend more than $100 million of his own money on his presidential bid. Steyer is also boosted by a pair of substantial email lists from those organizations that his campaign has since rented and used. He has additionally spent millions so far on Facebook ads

Earlier Tuesday, Steyer told MSNBC's "Morning Joe" that he is running as an "outsider" to "take back the government from the corporations who bought it." Steyer also defended his support for impeachment, saying he doesn't "buy any part of that argument that telling the truth and standing up to a corrupt and wrong-headed president is somehow bad politics."