...the bottom line is this: What motivates them? Why have so many RightWing pundits and bloggers and commentators and political leaders seemingly dedicated their lives to destroying John McCain?

Why are they trying so hard? They're not really disembodied brains floating in Bell jars--the passion behind the dry recitations of crimes against Republicanism comes through despite the pose of Vulcanism.

ER made some interesting observations about the necessity of maintaining discipline for revolutionary minorities trying to take over a moderate society. It's like the technique for scaring off a mountain lion: Try to look as big and menacing as possible to cow and demoralize the opposition. Any whiff of dissent in the ranks makes the whole appear smaller as people discern its component parts, and opens up the possibility that the moderate majority might "shop around" and negotiate a less radical deal with one of the factions.

Is the Conservative base inside the Republican Party a revolutionary minority? Ask Newt Gingrich why he called it the "Republican Revolution". Or Hugh Hewitt about his "permanent Republican majority". Or examine the high priority given to packing the courts with lifetime judges to bind America to a particular ideology, regardless of how opinion might shift in the future. What percentage of Americans do you honestly think share 100% of the views of the Conservative ideological purity checklist? 10%? 15%? Not much more than 20%, I'd say.

Or listen to the rhetoric, in which Conservatives stridently maintain that they represent the mainstream of American thought, while simultaneously attacking mainstream institutions such as the press, education, the judiciary, and so on. That's the scare-the-mountain-lion tactic in action: Present a larger profile than you actually possess, and try to minimize the perceived size of your opposition.

One of the well-understood purposes of hyperpartisanship is to narrow and eventually destroy the moderate middle. In other words, attack from the other direction the threat that the moderates might negotiate with a faction, by diminishing the moderates; and simultaneously, give your dissenters fewer places to find sanctuary should their revolutionary resolve falter. If you can polarize a society to such an extreme degree, nobody can be a moderate, everybody must be a radical...and then, as ER points out, your opponents can easily be demonized.