Senator Arlen Specter apparently is the newest Democratic member of the US Senate.
As The Fix notes:
Because of the shrinking Republican vote in the state [of Pennsylvania], Specter was seen as a dead man walking politically in the primary with polling showing him trailing [Republican primary challenger Pat] Toomey by ten or more points. The bar for Specter to run as an independent was also extremely high due to the rules governing such a third party candidacy.
That left a Democratic candidacy as Specter’s best option if he wanted to remain in the Senate beyond 2010.
And Specter himself justified his decision by saying “Since my election in 1980, as part of the Reagan Big Tent, the Republican Party has moved far to the right. Last year, more than 200,000 Republicans in Pennsylvania changed their registration to become Democrats. I now find my political philosophy more in line with Democrats than Republicans.”
Now, one might say that was a convenient “finding.”
But should we see this as “agency loss” (he was elected as a Republican, after all) or as “agent responsiveness” (his principal–the electorate of Pennsylvania–has shifted its preferences in the last five years)?
Whatever our answer may be in the case of the current US Senate and Pennsylvania, would it vary if the electoral system or constitutional context were different?