The decision of Republican Senator Arlen Specter to return to the Democratic Party after 28 years as a Republican is the best thing that could have happened for Republicans and the worst for Democrats. What do Democrats get out of this deal that they didn't already have? What do the Republicans really lose? The answer is the same for both questions, nothing.
One of the reasons cited by the Senator for swapping his party affiliation has to do with the polling numbers showing that he would likely not win a Republican primary in his home state. Not wanting to lose his job in the next election he went to the Democrats who offered to let him run as a Democrat in the next election in exchange for his crossing over now.
It has been said that Obama agreed to campaign for him and that he might be allowed to sail through the primary without a serious challenge. Why would Democrats want to do that? What do they gain? Why would they want to take someone into their party who is so quick to change party affiliation when a hard primary approaches? Can you count on such a person?
What did Republicans lose? Many on the right have long wanted Arlen Specter gone from their party. Challenging an incumbent is a hard thing to do. Incumbents traditionally have the support of the national party in the primary on the off chance they are challenged. With Specter running as Democrat the party is free to have a primary with no incumbents running. The state party members get a real chance to elect someone they want as opposed to fighting against the status quo.
I would like to point out the recent case of Senator Joe Lieberman. Joe was targeted by the extreme left wing of his party because he dared to support the Iraq war. Much like Specter he was often seen as a problem by members of his own Democratic party. Lieberman faced a primary challenge in the form of one Ned Lamont. After being defeated in the primary (where only the fringe members vote according to Specter) Lieberman saw all of his long time Senate friends move their backing to the party favorite. Knowing that he had the support of the majority of CT voters he ran as an independent and won.
That's right. Joe Lieberman found himself in nearly the same position Arlen Specter finds himself in right now, facing a tough primary that he may lose. Joe did not give up. He knew the voters would support him so he ran in the general election and he was proven right, defeating both the Democratic and Republican challengers!
What do we learn from Joe? We learn a lesson that Arlen Specter has not learned. We learn that if the people respect and believe in you they will vote for you no matter what party you belong to. Even when your party sends a primary challenge your way that appeals to your parties 'fringe' base and not the electorate at large you can still win. Joe did it.