Serious grumblings on the GOP side.....

While the Dem divisions among Obama and Clinton supporters are almost entirely about personality not policy differences, the GOP seems to be flaking off a number of its constituencies.

First you have the Libertarian fracture, primarily over the war in Iraq. Bob Barr is trying to run on the Libertarian ticket with a seemingly entire goal of taking a chunk out of McCain. (Please ignore the cheesy moustache.)

Next, from inside the Republican party, you have the "Libertarian" Ron Paul supporters who are still organizing, turning out for primaries, trying to take over the state conventions, and even threatening to stage a revolt at the GOP convention.

Then, there's the floating and as yet unorganized Christian Right opposition to McCain which hasn't yet taken too solid a form, but is certainly out there. (Just wait til the abortion plank comes around at the convention.)

Plus, the Tancredo immigration folks aren't too horribly pleased about McCain.

None of these are likely to be huge defecting constituencies, but each will act as a siphon from the right on McCain's support, and collectively, they might mean real points in the general election totals or in particular states.

As we sit and talk about a Democratic Party divided, I think we ought to keep in mind that the Dem problems with their candidates are relatively minor. McCain has passionate dissenters on policy.