Sentient political observers will note that the case for John McCain is often framed in the negative. Sure, everyone stipulates McCain has something going for him. There is the usual recitation of the man's character. McCain served his country ably and honorably in Vietnam, battered but unbowed by five and a half years of captivity in Hanoi. Some point to his lengthy record in the Senate. McCain is a hardliner against excessive spending and government waste, for example. He has proven himself a "maverick," often bucking partisanship in favor of principle, obscure though that principle may be.

But beyond that, little can be said in McCain's favor. McCain may be an honorable man, but his honor is eccentric. And, in any event, honor is a tough sell to people who have little understanding of the concept. Meantime, the conservative case against McCain is so well known by now that it hardly bears repeating. Instead, the campaign is all about Barack Obama and his character, his experience, his qualifications to be Leader of the Free World. The case for McCain has become, over the past few months, the case against Obama. Even the McCain campaign has embraced this reality, as those recent ads mocking Obama's messianic campaign and comparing him to Britney Spears and Paris Hilton suggest. Truth is, attacking Obama is just about the best option McCain has.

On that front at least, McCain can count on some conservatives for help. Two new right-wing tracts against Barack Obama hit stores this week -- Obama Nation by Jerome Corsi (of Unfit for Command fame) and The Case Against Barack Obama by David Freddoso. I haven't had a chance to read either book yet, although I flipped through Corsi's at a bookstore on Saturday. I think I'm partial to Freddoso. The books follow Hugh Hewitt's Letter to a Young Obama Supporter, which seeks to disabuse young, would-be Obama voters of the idea that their candidate is all about Hope and Change. And this onslaught of anti-Obama literature arrives just as the insipid media "debate" turns away from whether the presumptive Democratic nominee is too inexperienced to whether he's too arrogant, presumptuous, "uppity" or whatever.

With the exception of "uppity" -- which Obama partisans and first-rate hacks like David Gergen, not Republicans or conservatives, have tossed like a dead cat's carcass into the discourse -- all of the charges are true. Arrogance bordering on hubris has characterized the campaign. "We are the change we have been waiting for"? "This was the moment when the rise of the oceans began to slow and our planet began to heal"? Contra Andrew Sullivan, who is easily distracted these days, Obama is at once too presumptuous and too inexperienced. He is both too liberal and too opportunistic.

Here's my theory: The election isn't a contest between Obama and McCain. It is America's first real national referendum. Obama: Yes or no? A vote for McCain is nothing more than a vote against Obama. McCain is a foil, a negation of Obama -- or, depending on one's point of view, an antidote to Obama's messianism. McCain is the answer to an ugly subtraction problem. Obama - Rev. Wright - Tony Rezko - Bill Ayers - his liberal voting record - rural "bitter people" - "Yes we can" - free trade miscalculations - Iraq withdrawal - tax hikes - Obama's ambivalence bordering on hostility toward mainstream America = John McCain.

So the case against Obama is simple enough. That's why he's struggling in the polls. Too bad the alternative is so unsatisfying.