I don't have much more to contribute regarding Paul Krugman's latest swipe at Obama. I think Aaron pretty much nailed it in his terrific "Stopped Clocks" post today.
While the main point of his column—“stick to substance, people, it’s where we’re strongest”— is valid enough, the notion that an Obama presidency would create a more rancorous environment than a second Clinton administration is sheer fantasy. And while the level of hostility aimed at the Clintons during the 90s was indeed hysterical, unfair, and undeserved, I do think that their shared bunker mentality—one that Krugman seems to advocate—only made matters worse (see the excellent New Yorker piece “The Choice” for more on this).
The only thing I would add is this: in titling his column "Lessons of 1992" and asking "Has everyone forgotten what happened after the 1992 election", Krugman is clearly criticizing the naivete of the early Clinton Administration in dealing with the Congressional GOP. Why would his lesson from that period then be that we should vote the Clintons back into office?