I don't know that Greg's right about the American Conservative Union's ratings being biased in one direction or another rather than simply inaccurate -- the ACU seems to give McCain more rightwing scores than the National Journal's system, and I won't pretend to have rigorously evaluated the comparative merits of the two. But Greg's overarching point is correct, and something I tried to flag in my debate with Chait: Since 2000, Democrats have been out of the White House and, save for a year of slim Senate majority, out of power. As a result, the actual legislation offered by Democratic senators and occasionally cosponsored by McCain was milquetoast, broadly-supportable stuff; the sort of consensus-seeking approaches that Democrats hoped would win over the House and the president, but ended up painting the party as spineless and energizing the Dean insurgency.
None of this is to deny the couple of areas where McCain is genuinely moderate: global warming, torture, campaign finance reform, etc. But they are few and far between. And compared with his fiscal austerity, his enthusiasm for military interventionism, and his conservative opportunism on social issues, the guy just isn't supportable.
