How Bloomberg could help Joe Biden take on Trump

Taking aim at President Donald Trump on Twitter Thursday, former New York City Mayor Mike Bloomberg tweeted an edited video mashup splicing together movie clips and dialogue to deliver the message that Democrats would unseat Trump next fall — ending with the hashtags "#Dump Trump" and "Go Joe."

It was the first time -- and definitely not the last -- Bloomberg has targeted Trump in support of former Vice President Joe Biden.

Bloomberg is launching a new independent expenditure effort to help elect the Democratic nominee, a campaign aide told ABC News.

The move comes after the former New York City mayor, who spent $600 million of his own money before ending his own White House bid on Wednesday, vowed to use his vast financial resources to help boost Biden and spend "whatever it takes" to defeat the sitting president.

"I’ve always believed -- I’ve always believed that defeating Donald Trump starts with uniting behind the candidate with the best shot to do it, and after yesterday's vote it is clear that candidate is my friend and a great American, Joe Biden," he told supporters and staff in New York on Wednesday.

Although the name, budget, and scope of the entity is yet to be determined, the aide confirmed to ABC News that the effort will including establishing offices in six battleground states: Arizona, Florida, Michigan, North Carolina, Pennsylvania, and Wisconsin.

The new operation would be pro-nominee and anti-Trump, the aide told ABC News, anticipated to be a huge help for the Democratic Party in the general election as the national party committee continues to be struggle with debt and lag behind its Republican counterpart in fundraising, while the Trump campaign and its joint fundraising vehicles rake in hundreds of millions of dollars.

Politically it remains to be seen when Bloomberg will begin his work. A careful reading of his statement doesn’t rule out attacking Vermont Sen. Bernie Sanders in the primary to help Biden win the nomination.

While no decisions have been made, Bloomberg's new operation could potentially begin supporting Biden in the primary by undercutting Sanders, who Bloomberg repeatedly argued would lose the election to Trump and imperil down-ballot Democrats.

But the difference between sending out pro-Biden leaflets in states with upcoming primaries and flooding airwaves with negative ads about Sanders is a sharp one. Aggressive efforts could also hurt efforts to unite the party in the fall.

Sanders on Wednesday appeared to relish Bloomberg's support for Biden and continued to use the billionaire former mayor of New York as a foil for his calls for a political revolution, while acknowledging that Bloomberg has the right to run negative ads about Donald Trump and fund get out the vote and voter registration efforts.

"It's his money. He has a right to do that," Sanders said during a nearly hour-long interview with MSNBC's Rachel Maddow on Wednesday. "All that I'm saying, Rachel, is the American people understand that the current political system is literally corrupt, that billionaires whether it's Michael Bloomberg or right wing Republicans who are spending hundreds and hundreds of millions of dollars to support right wing candidates, that is a corrupt political system, and we've got to change it."

One thing clear at this point is that Bloomberg's new operation will not be able to coordinate with the Biden campaign as federal election laws prohibit outside spenders from working with the campaign.

"Bloomberg can keep his offices open and his staff employed--all to support Biden--with Bloomberg continuing to pay for it, but the work needs to be done independently of the Biden campaign," Paul S. Ryan of nonpartisan watchdog group Common Cause told ABC News. "In other words, Bloomberg can run a pro-Biden super PAC, using his campaign office space and campaign staff. Bloomberg's pro-Biden effort staff couldn't coordinate it's spending with the Biden campaign."

It might not even be necessary depending on how the rest of the primary plays out given Biden’s expected strength in some of the upcoming contests.

Asked if Bloomberg would run ads against Sanders on MSNBC on Wednesday, campaign manager Kevin Sheekey did not rule it out, only noting that the campaign was still running previously-reserved ads attacking Trump.

"Let's just say we're running a fully negative campaign and we'll see how it goes," he said.

Before he suspended his campaign, Bloomberg’s team sketched out an aggressive effort focused on Florida and five other battleground states, mobilizing voters and relentlessly pounding Trump. Bloomberg's campaign told ABC News that will be paid through the end of March.

Bloomberg's new operation will also help support down-ballot Democrats, the aide said.

And Hawkfish, the Bloomberg campaign’s primary digital agency that supports Democratic campaigns and was founded by the former mayor himself, will continue to exist as a separate entity, the aide said. Bloomberg poured millions of dollars into developing Hawkfish ahead of his presidential run aimed at closing Democrats' digital gap with the sophisticated digital operation that helped Trump win the White House in 2016.

Over the years, the former New York City mayor funneled hundreds of millions of dollars into boosting Democrats, not only as one of the biggest donors major party-linked super PACs spending to elect Democrats to Congress but through two political groups founded and funded by himself.

Just in the 2018 election cycle alone, Independence USA, a super PAC founded and funded by Bloomberg that could serve as a vehicle for his plans after dropping out of the 2020 race, spent more than $110 million in supporting more than 20 Democratic candidates in House races, including Georgia Rep. Lucy McBath and California Rep. Harley Rouda, who have both endorsed his now-wrapped presidential run. A political arm of Bloomberg's pro-gun control group Everytown for Gun Safety spent millions to support Democrats in the last midterms.

And Bloomberg has already been active with non-presidential races and political spending in 2020.

Just in December, Bloomberg donated $10 million to pro-House Democratic group House Majority PAC and $5 million to the new Stacey Abrams-linked group, Fair Fight. In November, he gave $800,000 to the Democratic Grassroots Victory Fund, a Democratic National Committee-linked fundraising vehicle, more than $300,000 of which went to the DNC directly.