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GRUNDY, Iowa — New debate qualification rules by the Democratic National Committee will open a path for former New York City Mayor Mike Bloomberg to participate in the party's Feb. 19 debate, hosted by NBC News and MSNBC at the Paris Hotel in Las Vegas.

The new rules require candidates to get at least one delegate out of either the upcoming Iowa caucuses or New Hampshire's primary, or to register 10 percent support in four national polls or 12 percent in two single-state polls of Nevada and South Carolina.

The party scrapped, for the first time, the grassroots donor threshold, which has required candidates in every other debate thus far to received donations from tens of thousands of supporters to qualify. That opens the door to Bloomberg, a multibillionaire who is funding his own campaign and has refused to accept any donations for his campaign.

"Now that the grassroots support is actually captured in real voting, the criteria will no longer require a donor threshold," said DNC spokesperson Adrienne Watson.

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"The donor threshold was appropriate for the opening stages of the race, when candidates were building their organizations and there were no metrics available outside of polling to distinguish those making progress from those who weren't."

The response to the new rules was fast and furious from some rival campaigns.

The campaign of Vermont Sen. Bernie Sanders suggested the DNC was doing Bloomberg's bidding.

"To now change the rules in the middle of the game to accommodate Mike Bloomberg, who is trying to buy his way into the Democratic nomination, is wrong," said Jeff Weaver, one of Sanders' top advisers. "That's the definition of a rigged system."

Brad Bauman, a senior adviser to Andrew Yang, said on Twitter, "If you look at the new DNC debate thresholds as anything other than 'Get Andrew Yang off stage and put Mike Bloomberg on,' Then you are high."

The threshold is a big step up from the one that will be used for next Friday's debate, between the Iowa caucuses and New Hampshire primary, which set the bar at only 5 percent support in four national polls.

So far, just three candidates appear to have registered enough support to make the stage: Sanders, Massachusetts Sen. Elizabeth Warren, and former Vice President Joe Biden.

Bloomberg and Pete Buttigieg, the former mayor of South Bend, Indiana, each have one qualifying poll, while the rest of the field has zero.

But Buttigieg and others, such as Minnesota Sen. Amy Klobuchar, are on track to get some delegates in Iowa and the window on polling does not close until Feb. 18, so more candidates are almost certain to make the grade.

The Bloomberg campaign hailed the new rules, though the candidate still needs to climb in the polls to actually make the debate.

“We are thrilled that voters could soon have the chance to see Mike Bloomberg on the debate stage, hear his vision for the country, and see why he is the strongest candidate to defeat Donald Trump and bring our country together,” the campaign's manager, Kevin Sheekey, said in a statement.