Bloomberg was a lifelong Democrat until 2001, when he switched to the Republican Party before running for Mayor. He switched to an independent in 2007, and registered again as a Democrat in October 2018.In 2004, he endorsed the re-election of George W. Bush and spoke at the 2004 Republican National Convention.
Solid credentials and a deeply loyal Party man.
I think Bloomberg has his own view of how things should be (soda, guns, diet, general nanny state). Party isn’t a religion for him, it’s a vehicle. I don’t think he cares about either Party, except as a tool for his ambition to affect and control society.