The great irony here is that McCain managed to use the same Manichean moralism to get the Senate and the House to go along with his anti-torture crusade. The administration argued for flexibility; McCain insisted on a bright line: The United States does not tolerate torture—finesse it as you wish, but that includes things like "waterboarding."
In short, you're either with us or with the torturers. McCain arguably beat the administration at its own rhetorical game.
I agree with George that McCain was on the side of the angels on this one (or, more precisely, on the side of humanity). But then why does McNasty have to be such a goddamn horse's ass on just about everything else, especially campaign-finance reform? On that score, check out former Federal Election Commission head Bradley Smith's piece in the December Reason, "John McCain's War on Political Speech."