The fireworks on the Democratic debate stage in Las Vegas Wednesday could get hotter as former New York City Mayor Michael Bloomberg has qualified to take part. It will be his first debate in this presidential race. It will also mark the first time his opponents will have a chance to take on the billionaire who they claim is trying to buy the presidency.

An NPR/PBS NewsHour/Marist poll released Tuesday gives Bloomberg 19% support nationally. Democratic National Committee rules for this debate required him to get at least 10% in four approved polls, which he now has.

There was speculation as to whether Bloomberg would take part in the debate even if he qualified. He is not on the ballot in Saturday's Nevada caucuses or next week's South Carolina primary. His first appearance will be on Super Tuesday, March 3. But his campaign has reportedly confirmed he will be there Wednesday.

Sen. Bernie Sanders opened up a double-digit lead in the poll with 31% support nationwide, an increase of 9% since this poll was last taken in December.

Bloomberg is second with 19%, but has shot up from 4% in December.

Former Vice President Joe Biden has fallen to 15%, a drop of nine points. He's followed by Sen. Elizabeth Warren at 12% -- down five points, Sen. Amy Klobuchar at 9% -- up five points following her third place finish in New Hampshire, and former mayor Pete Buttigieg at 8% -- down five points.

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Bloomberg's Democratic opponents have criticized him for, they claim, trying to buy the election -- a sign of how seriously they are taking him. Bloomberg, who is worth an estimated $64 billion according to Forbes, has spent a reported $400 million on his campaign. But he hasn't taken part in a debate until now. His message is getting out via personal appearances, digital and social media, and an onslaught of television ads aimed primarily at President Donald Trump. 

Buttigieg and Sanders are in Wednesday's debate for having won at least one national delegate, but they also hit required polling thresholds. Biden and Warren are in based on polling. Klobuchar is in based on delegates she won, but has qualified in only one poll.

Billionaire Tom Steyer will not qualify for the debate. It will be the first one he has missed since June, before he entered the race.

Bloomberg and Sanders mix it up

Bloomberg tweeted a video mashup Monday of aggressive and threatening comments made by people who appear to be Sanders supporters, juxtaposed with Sanders calling for “civil discourse.

Bloomberg said such aggression won't give Democrats the unity they need to beat President Donald Trump. It was in response to a speech by Sanders in which the senator said the former mayor would not generate the necessary excitement to beat Trump.

Sanders, campaigning in Washington state Monday, denounced any such comments made by people who claim they are backing him and said he wants his supporters to argue the issues, not make personal attacks.

"Anyone who says that they are supporting me who is saying terrible things about anybody else is not really supporting me. I don't want their support," Sanders said.

Speaking at a town hall in a Las Vegas suburb Monday, Warren preached for unity within the Democratic party as necessary for defeating Trump.

Buttigieg, who has struggled in polling among people of color, is trying to earn a fresh look from black and brown voters by flashing his support in the first two contests, drawing on the validation of minority leaders who have endorsed him and leveraging the personal networks of his supporters.  

Klobuchar is joining Steyer, Sanders and Buttigieg in launching Spanish-language television ads in Nevada. Latinos make up 29% of Nevada’s population. Klobuchar's ad features a Spanish-speaking narrator who says Klobuchar is a candidate who can defeat Trump and fight for better health care and prices for prescription drugs.

All six candidates who will be on stage Wednesday are likely to be at the debate in South Carolina next Monday. The requirements to qualify are virtually identical. As of Tuesday morning, only Bloomberg had yet to qualify.

After South Carolina, it's Super Tuesday. By then, more than one-third of the delegates will have been awarded. Campaign operatives tell the Associated Press that if someone emerges from Super Tuesday with a significant lead, it will be extremely difficult to catch them.