New York Democrats are particularly angered by his previous donations to Republicans, including some in the not-so-distant past. While spending about $100 million to help Democrats flip the House and win other midterm races last year, Bloomberg simultaneously donated to then-Rep. Dan Donovan, a Staten Island Republican, and held a fundraiser in June for Rep. Peter King, a Republican who represents parts of Long Island.

Co-hosts were asked to collect $10,000 for King. Bloomberg also showered New York Republicans with money when he was mayor, which helped them keep control of the state Senate.

“The path to win the House ran through New York: There were seven flippable seats in the state, and he supported Republicans in two of them,” said Monica Klein, a former consultant for Liuba Grechen Shirley, King’s 2018 Democratic opponent. “To come down and say he wants to be the head of the Democratic Party — the hubris is unbelievable.”

Bloomberg’s aides are addressing the issue of his past donations by highlighting that he has backed Republicans who support his priorities, such as liberal gun policies. He has also attempted to blunt criticism about spending his fortune on his own presidential bid by pledging to donate $100 million to an anti-Trump digital campaign.

“As mayor and as the country’s leading gun safety champion, Mike has supported Republicans in the past, including Republicans who helped deliver aid to New York after 9/11 or who crossed the aisle to vote for gun safety in Congress,” Bloomberg spokesman Jason Schechter said..

Gun control groups aligned with Bloomberg have thrown their weight behind some Republican candidates as well, in some cases giving them much-needed bipartisan bona fides. Everytown for Gun Safety, a nonprofit founded by Bloomberg, endorsed Rep. Brian Fitzpatrick (R-Pa.) in a Philadelphia-area swing district in 2018.