Giuliani is just one of many skeletons in Bloomberg’s partisan closet. As he pursues the Democratic nomination, he’ll have to explain away the millions he’s spent putting Republicans into office, including contributions backing more than a dozen current and former Republican members of Congress.

The billionaire businessman, who has switched parties several times throughout his political career, endorsed George W. Bush’s 2004 reelection campaign, contributed to John McCain and even held a fundraiser for a House GOP member as recently as last year…

“As a Democratic candidate for president, he makes an excellent Republican donor,” quipped Pennsylvania Democratic Lt. Gov. John Fetterman, who has not yet endorsed anyone in the primary.

Though Bloomberg has also spent millions to support Democrats in recent years, some Democratic elected officials and party operatives remain bitter that he worked to defeat them up and down the ballot in the past.