It’s a big day for Democratic Senate primaries, with Arkansas and Pennsylvania going to the polls to challenge the tenure of Blanche Lincoln and Arlen Specter. While I don’t know what the outcome will be of these elections (I’d guess Lincoln gets a plurality but there is still a runoff and Specter barely loses), it’s clear that both primaries have forced the sitting senators to behave more like Democrats. Specter has evolved from a major roadblock in the Democratic agenda to a top cheerleader for things like healthcare reform and even labor reform. And Blanche Lincoln has recently put forward language in a derivatives bill that is far stronger than anything emerging from Chris Dodd or Barney Frank, two of the more liberal Democrats on the Hill. Neither of these senators would have been behaving like Democrats if they didn’t have to face a Democratic primary challenger and Democratic base voters today.

As Jane Hamsher points out, what is happening in the Democratic Party is normal and healthy. It is not a product of extremists in the base, but rather that Specter and Lincoln have been morally pliable and often times available to vote for whichever business interest group makes the strongest play for them. That’s not principled nor centrist – it’s insiderism that ignores the needs of voters. As a result, voters are prepared to punish them.

Unfortunately, Blanche Lincoln’s insiderism has another noticeable symptom: cynicism.  While I mentioned above that Lincoln has introduced incredibly strong derivatives reform which has won well-earned praise from progressives for its effort for real, meaningful change, she is now prepared to pull back the language after today. To repeat: she offered a bill that Democrats in Arkansas and nationwide loved, days before a primary for her life, and is now saying she may drop the language as soon as the primary is over. This is quite possible the most cynical move I have ever seen in American politics (and I lived in Alaska when McCain picked Palin as his running mate).

Obviously I hope Lincoln is defeated by Bill Halter today. But more importantly, I hope that Senate Democrats do not allow Lincoln to withdraw her worthy and beneficial language as soon as its political usefulness has past its expiration date. Complicity by Senate Democrats to help Lincoln survive a primary is no less cynical and no less disgraceful. It’s clear that Lincoln is a blight on the Democratic caucus, hopefully soon to be excised, but it’s hard to imagine either her or this once proud body ever stopping to such cynical lows as they may be poised to do around Lincoln’s derivatives language.