Last year, U.S. Senator Arlen Specter of Pennsylvania changed his registration from Republican to Democratic, after he and others in Pennsylvania realized that he would probably lose the May 18, 2010 Republican primary.
Now, however, he is trailing in the Democratic primary. Slate has this interesting article by Steve Kornacki, asking whether Specter would have been wise to change his registration last year from Republican to independent, and to have run for re-election this year as an independent.
Ironically, in 1997, Specter tried to make Pennsylvania ballot access far more difficult. He used his influence with Pennsylvania Republican legislators (who were in the majority in both houses) to get a bill through the legislature, quadrupling the number of signatures for independent and minor party candidates. The bill passed, but fortunately Governor Tom Ridge vetoed it.
The reason Specter tried to make ballot access for independents and minor parties more difficult back in 1997 is because he was up for re-election as a Republican in 1998, and he hoped to prevent the Constitution Party from getting a candidate on the ballot against him. Specter has always been pro-choice, and he had seen how well the Constitution Party had polled in the 1994 Pennsylvania governor’s race, when the Republican Party nominee for Governor had also been pro-choice. As things turned out, Specter was overwhelmingly re-elected as a Republican in 1998. Although the Constitution Party did get on the ballot against him, it only polled 68,377 votes.