Peter Beinart says that Lamont and his supporters are more opportunistic than principled. This is meant to puncture the McGovern-Lamont comparison and to encourage Democrats to think in a principled way. I fear, however, that if they find principles, they wont be Beinarts, but rather McGoverns. (In other words, I dont take as seriously the vaguely hawkish noises that punctuate the cut-and-run chorus.)
For a somewhat different view, focusing on how narrow the gap in 2008 will be between any two administrations, see this post by Power Lines John Hinderaker:
As a practical matter, I question how much the Democrats apparent tilt to the left will matter in policy terms. Its true, in principle, that a hard liberal like Feingold will be less inclined to use American military force in post-Iraq situations than a more conservative Democrat, or a Republican. But the reality is that no administration that takes office in 2009, Republican or Democrat, will have any appetite for another ground war in the Middle East. For the foreseeable future, that isnt going to happen, no matter who inhabits the White House.
That leaves Iran, and the prospect of using force short of an invasion to prevent or deter Iran from becoming a nuclear power. What the Democrats intend to do about Iran is a dark secret, and, if they have their way, will remain one until 2009. Their only strategy at present is to be well-poised for second guessing. But it looks increasingly as though Iran cant wait until 2009. One way or another, that problem will have been addressed by the time the next Presidential election rolls around, and the debate will have shifted in ways that we cant now foresee.
So I think the most that can be said is that an antiwar Democratic administration will be somewhat less likely to use military force, as a general matter, than a Republican administration would be. But, given our experience in Iraq, that gap may not be very wide.
His assumption seems to be that events will compel GWB to come as close as possible to finishing the job before his successor assumes office.