Michael R. Bloomberg still has not declared whether he is running for president in 2020. He is about to become the single biggest spender in the presidential race anyway.
Ahead of a potential campaign announcement, Mr. Bloomberg, the billionaire businessman and former mayor of New York City, is beginning a $100 million digital campaign designed to attack and define President Trump in the top battleground states seen as likely to decide the 2020 election. The ads will go online on Friday in four states — Arizona, Michigan, Pennsylvania and Wisconsin — and run through the end of the primary season, even if Mr. Bloomberg is not in the race.
In a twist, Mr. Bloomberg himself will not be featured in the ads beyond legally required disclaimers, even as he actively lays the groundwork for a campaign, his advisers said. The $100 million ad buy will be in addition to whatever Mr. Bloomberg may spend on efforts to promote himself to become the Democratic nominee.
“We will have other ads that feature Mike Bloomberg,” said Howard Wolfson, a top political adviser to Mr. Bloomberg. “You will be seeing a lot of Mike Bloomberg.”
The Bloomberg team declined to preview the content of the ads ahead of their release, other than to say they would feature anti-Trump content.
The spending is an unprecedented financial show of force and a pre-emptive strike to undercut the expected Democratic complaints that Mr. Bloomberg’s money would be best spent on Democratic priorities, rather than his own presidential ambitions. It also delivers the unsubtle message that if Democrats were to nominate Mr. Bloomberg, his immense wealth could tilt the financial playing field of 2020 in their favor.
“We’re very clear: A case that we make for Mike is that he is the best candidate to take on Trump, and one of the reasons he is the best candidate is he can take the fight to him immediately and robustly,” Mr. Wolfson said.
Some Democrats have fretted for months that Mr. Trump’s campaign was using its financial edge to swamp Democrats online, with Mr. Trump spending more than $27 million so far just on Facebook and Google. Earlier this fall, Mr. Trump’s campaign announced it had entered October with $158 million cash on hand in its campaign and shared accounts with the Republican National Committee. And in the 24 hours after the first congressional impeachment hearing this week, Mr. Trump’s campaign said it had raised $3.1 million in small donations.
“If you believe, as Mike Bloomberg does, that Donald Trump represents an existential threat to our country, it is an all-hands-on-deck moment,” Mr. Wolfson said. “The thinking is that the general election has started.”
The list of swing states included in Mr. Bloomberg’s anti-Trump campaign would most likely grow in the future, Mr. Wolfson said.
Mr. Bloomberg also spent heavily in the 2018 midterms, pouring about $100 million into Democratic efforts, particularly to win control of Congress. Democrats won 21 of the 24 House races he invested in.
The new anti-Trump campaign by Mr. Bloomberg is the second major infusion of Democratic money into online advertising in two weeks. A new progressive organization, Acronym, announced earlier in November that it and an affiliated PAC were investing $75 million in online ads in battleground states.
That group, advised by David Plouffe, who managed Barack Obama’s first presidential campaign, was focused on the same four states as Mr. Bloomberg, plus North Carolina. Mr. Plouffe said Acronym’s goal was to ensure that whoever emerged as the party’s nominee was not in a “hole too steep to dig out of.”
In addition, Priorities USA, the leading Democratic super PAC in the 2016 race, has said it plans to spent $100 million, including on digital ads, its analytics program and on television, through the convention. The group held a briefing this week on its anti-Trump program and said that, since late July, its PAC had actually outspent Mr. Trump’s campaign in the four battlegrounds where it was advertising: Florida, Michigan, Pennsylvania and Wisconsin. The group noted that much of Mr. Trump’s spending had been targeting new donors versus trying to persuade swing voters.
Priorities USA also announced that it would expand to Arizona, one of the states that Mr. Bloomberg is targeting, with a $2 million digital buy.
Mr. Bloomberg has flirted with running for president before — including as an independent in 2016 — but he has taken concrete steps toward a Democratic primary campaign in recent days, including submitting paperwork to appear on the ballot in Alabama and Arkansas, the states with the earliest filing deadlines.
The disclaimer on Mr. Bloomberg’s personal website was recently changed to “Paid for by Mike Bloomberg 2020,” which campaign finance experts said suggested a formal filing could be imminent.
Mr. Bloomberg’s advisers have said that if he runs, he will focus on the delegate-rich states that vote on Super Tuesday in March, such as California and Texas, where the cost for most other campaigns to buy substantial advertising would be prohibitive.
The filing deadline for New Hampshire, which holds the first primary contest after Iowa’s caucuses, is Friday, but Mr. Bloomberg is not expected to file to be on the ballot there, his team said.
If he does run, Mr. Bloomberg would be the second billionaire to enter the Democratic field, following Tom Steyer, a former hedge fund manager. Mr. Steyer has said he would spend $100 million of his fortune on a campaign, and he had already spent nearly $50 million as of the end of September.
Mr. Steyer’s heavy advertising in the early states has delivered him enough support in polls to qualify for the November debate, which will take place next week.
But such free spending from billionaires has threatened a potential backlash among the progressive base.
“Call me radical, but maybe instead of setting ablaze hundreds of millions of dollars on multiple plutocratic, long-shot, very-late presidential bids, we instead invest hundreds of millions into winning majorities of state legislatures across the United States?” Representative Alexandria Ocasio-Cortez of New York, who has endorsed Senator Bernie Sanders of Vermont, wrote on Twitter on Thursday. “Just a thought!”