As Michael Bloomberg wages a war of words with Donald Trump over Twitter, the former mayor’s past flattery of the current president is coming back to haunt him. “I’m a big fan of Donald Trump,” Bloomberg told ABC News in 2011. He later admitted to being a “friend” of the “New York icon” in a Fox interview, downplaying the future president’s leading role in the birther conspiracy theory about Barack Obama.

Similar video was unearthed by Politico, showing Bloomberg in 2016—a month after Trump defeated Hillary Clinton—describing the then-president-elect as a “nice person.” “Yes, Donald, I do love you,” he recalled telling Trump, post-election. “I just disagree with everything you’ve ever said.” Sanders, who has opened a double-digit lead over the rest of the 2020 Democrats in recent days, shared a photo of Bloomberg and Trump as golf buddies in response to an attack by the former mayor’s campaign describing the president as “Bernie’s new bro.”

Bloomberg’s chummy treatment of Trump in the past highlights the rarified world both men lived in, and the resurfacing of flattering remarks and photos is reminiscent of images of Clinton yukking it up with Trump at Mar-a-Lago a decade before they became bitter, political rivals. Similarly, Trump and Bloomberg routinely rubbed elbows at events in New York and on the golf course, trading praise for one another. “If there is anybody who has changed this city, it is Donald Trump,” Bloomberg said in 2013, commemorating the conclusion of construction on Trump’s Bronx golf course. “You have been a great mayor,” Trump returned. “I mean, this guy is fantastic.”

The scrutiny on Bloomberg’s relationship with Trump is already providing a potent line of attack for his 2020 rivals, with Joe Biden using the Fox clip in a campaign ad released Wednesday morning. It could also come up Wednesday night as Bloomberg makes his first visit to the debate stage, where he’ll likely have to answer directly to his opponents for his controversial record, including the stop-and-frisk policy he oversaw as mayor, his rhetoric on women and minorities, and charges from Sanders and Elizabeth Warren that he is seeking to buy the Democratic nomination with his vast wealth.

Bloomberg’s previous fondness for Trump could prove the most damning line of attack against him. Some Democratic voters might be willing to forgive parts of his record he’s since tried to distance himself from, if they believe him the candidate best positioned to evict Trump in November. It may be harder for those voters to accept as their savior from Trump a guy who appeared, as mayor, on his reality television program. Bloomberg’s campaign downplayed the former mayor’s relationship with Trump, telling Politico that “he hired Donald Trump to run a city golf course, and that’s the only job he’s hired him for.” But it remains to be seen if that’s enough to inoculate him against attacks from rivals who may not share his vast resources, but at least do not carry unfortunate photos with Trump in their baggage.

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