Bloomberg switched parties to win the office.
He was always a democrat. He lost before.
http://topics.nytimes.com/top/reference/timestopics/people/b/michael_r_bloomberg/index.html
He was always a democrat. He lost before.
Agree with the first two sentences. But I am unaware of any losing attempts at public office as a 'Rat prior to his successful run for mayor in 2001.
The common belief is that he switched parties in 2001 to avoid the stiffer opposition he would have had in the Democratic primary.