In her crusade to increase taxes on the wealthy, Senator Elizabeth Warren is going after the billionaire in the presidential race who opposes her plan — and she's targeting him in his own territory.

The Democrat's new ad, which she unveiled on Twitter, will air only once in New York, the city Michael Bloomberg ran as mayor, and only on Bloomberg TV, which he owns.

While donning a casual hoodie, Warren complains about the uber-rich guys who "call their billionaire friends and urge them to run for president" to avoid more taxes.

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The ad displays photos of Bloomberg while Warren says, "Some people have figured out, you know, it would be a lot cheaper to spend a few hundred mil just buying the presidency instead of paying that 2% wealth tax."

I guess some billionaires figured it'd be a lot cheaper to spend a few hundred million to buy the American presidency than paying their fair share in a #WealthTax so that everyone can succeed. I put an ad on Bloomberg TV to let them know—I'm not backing down from this fight. pic.twitter.com/cULpOZYKoh — Elizabeth Warren (@ewarren) December 4, 2019

Warren has created a campaign out of combating inequality. Her website sells mugs from which you can drink "billionaire tears." She was the first candidate to propose taxing not just the income of the wealthy but their assets — stocks, retirement funds, real estate. Her plan would impose a 2% annual wealth tax on people worth $50 million.

"When you make it big in America — I mean really big — pitch in two cents, so everybody else gets a chance to make it," she told reporters last month. "We can invest in an entire generation. We can rebuild a middle class. We can expand opportunity to children who've never seen it before. We can jumpstart our economy and build it from the roots up."

Senator Bernie Sanders has also proposed a wealth tax. His would be even more aggressive, with an 8% tax on people worth more than $10 million.

Mayor Pete Buttigieg and Tom Steyers, the other billionaire in the race, are the only other candidates to support Sanders or Warren on this idea.

In just one week, Bloomberg has already spent $13.2 million on TV ads in the 14 Super Tuesday states, according to CNBC. That's more than the combined total of what his rivals have spent in those states so far.

Other candidates have complained about the inequity in the race.

"I was in the hotel room [in New York] and I saw, I think, seven Bloomberg ads and two Steyer ads, and I thought, 'This is all people are seeing here,'" said Senator Amy Klobuchar. "You just shouldn't be able to buy a victory. That is not how we have run our campaigns, and that's not how our democracy runs."

Bloomberg joined the race late — just days before Thanksgiving — but his campaign has already endured quite a bit of controversy.

Bloomberg News announced in November that it would not launch in-depth investigations of any of the Democratic presidential candidates, including Bloomberg — who is on record saying, "I don't want the reporters I'm paying to write a bad story about me." In response, President Trump's reelection campaign said it wouldn't give Bloomberg reporters any press access to campaign rallies or events.

Last year, Bloomberg said he would sell his media company if he ran for president — or go into a blind trust. Neither has happened.