Specter’s switch from the Republican to the Democratic Party briefly gave Democrats a filibuster-proof majority and allowed them to pass the Affordable Care Act.
Joe Lieberman, the moderate Democrat and former longtime senator, lost a Democratic primary in Connecticut in 2006, largely over his support for the Iraq war.
A defection without a differenceArizona Sen. Kyrsten Sinema appears to be different as she becomes the 22nd senator to change party affiliation while in office.
A Senate independence trioSinema will be the first independent senator who isn’t from New England in more than a generation.
The most complete political evolution may be that of Lincoln Chafee, the Rhode Island politician who was a Republican senator, independent governor and failed Democratic and Libertarian presidential candidate.