I appreciate Kevin's point that progressives shouldn't underestimate the objective political difficulty of taking some of the stands we'd like to see people take. The other side of this, though, is that nervous Democrats seem to me to consistently overrate the political advantages of caving in. Matt Stoller has a great example here in Jason Altmire. He's a freshman Democrat in a district that leans slightly Republican -- a promising pickup opportunity for the GOP. So Altmire wants to be cautious. He went to Iraq, saw the propaganda show there, and returned proclaiming "The president has made the decision to continue the mission at its current level, and I am never going to vote to withhold funding to our brave men and women when they are out in the field of battle serving in harm's way."

Has this led the Pennsylvania GOP to laud Altmire as a hero of the Terrorists' War on Us? Of course not. He's a freshman Democrat in a vulnerable district, so here he is being fiercely attacked as a an advocate of "surrender," a proponent of "retreat and defeat," and of backing a "slow-bleed strategy to choke-off funding for the troops in harm's way."

Given the nature of the situation, if Altmire's position was to the left of where it is, he would have to weather these potentially damaging attacks. But he could also punch back against his attackers as proposing to give a blank check to an incompetent and unpopular president. He could defend the case for withdrawal on the merits, and complaining about wasting the lives of America's young men and the vast resources of our country on the president's ego trip. Maybe it would work. Maybe it wouldn't work. But the line Altmire's taken hasn't spared him from the attacks he's worried about. Instead, it's only made it harder for him to fight back against the attacks he got.

And that's the way it goes. If a guy like Joe Lieberman whose seat the GOP couldn't possibly take wants to shift right then, sure, the Republicans will hail him. But it's the people with vulnerable seats who are most inclined to do this stuff but it doesn't convince the Republicans to lay off -- they're not idiots, they go for the low-hanging fruit, not the politicians with the most objectively un-conservative voting record (Democrats unclear on this concept can probably ask Jim Leach for a primer since he's got spare time on his hands these days).

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