The Left vs. Right divide goes deeper than politics. It is also a "culture war" which is, to a substantial degree, a matter of reason vs. faith.
Reason has potency. But faith, for better or worse, is often far stronger. It has been so in most cultures during most periods of human history. The ascendence of the Religious Right in the US was not an aberration, it was a relaxation – a "blessed" relaxation, one might say – of a collective human nature that's been stretched out of its indigenous state for a time.
Reason is by nature self-debating and quarrelsome. Philosophers and thinkers argue. It's what they do. The topic can be anything – ethics, justice, military strategy, the meaning of life. Science, a pinnacle of the climb towards reason, is about argument too. A theory is persistently debated and challenged until it is mightily proven. (And even sometimes afterwards – cf. evolution).
By "faith," I do not mean only religious faith, which is what makes fundamentalists so violent (like Islamist terrorists) or socially destructive (like the Sarah Palins of the Christian world). I also mean unthinking adherence to any dogma. Bush, in his "stay the course" phase, was guilty of faith. The neocons were guilty of faith. American Communists in the 1930s were guilty of faith. Libertarians, when they deny realistic limits on their philosophy, are guilty of faith.
Liberals – or "progressives," as we're now supposed to call ourselves – are guilty of faith, too, when we let our convictions blind us to realities. Our curse is that we endeavor to remain on guard against lapsing into faith, with the result that we are often seen questioning ourselves, and when that happens we lose our political appeal.
It happens to Barack Obama all the time. Asked a question, he doesn't (always) spout ideology. He thinks a moment, then gives a considered, nuanced answer. That's tough to handle for an audience accustomed to digesting only soundbites.
Reasonable people question and debate. Often a sensible consensus arises out of the flurry. But sometimes we end up tangled in a web of uncertainty that prevents decisive action. And people who feel insecure don't want to see uncertainty in their leaders. As Bill Clinton put it, "When people feel uncertain, they'd rather have somebody who's strong and wrong than somebody who's weak and right." That insight is all one needs to explain George W. Bush's wartime reelection in 2004. It also helps explain John McCain's appeal at a time when most Americans disapprove of how his party has run the country.
Since the time of FDR, Democrats have won the White House only when they've fielded a candidate with extreme charisma (JFK, Clinton) or an aura of religious faith (Carter). When they lack either of those, the Democrats, because they incline towards reason, tend to look weak (Mondale, Dukakis, Kerry). This factor becomes especially important during periods of national turmoil, such as war.
Obama presents an interesting variation on this pattern. He certainly possesses the requisite charisma. Yet he is so publicly an intellectual that the Orwellian Right can – absurdly, but effectively – pin the "elitist" tag on him, having warped the sense of yet another once-useful word (cf. "liberal"). Also, because of Obama's background, the Right has been able to question his religious faith, even though, to anyone who has taken a little time to learn about him, that faith is obviously as authentic as Carter's. (It seems more heartfelt than that of Hillary Clinton, too. John McCain, ironically, hardly even pretends to be religious). As a result, Obama's religious faith isn't broadening his appeal the way it would for most other politicians.
The Right has screwed up so badly that they've given the Democrats a big chance. Even so, the latter need a superb candidate. Can Obama ultimately be that uniting figure? Can he walk the lines between his intellect, his charisma, and his faith steadily enough to appeal to independent and moderate voters? We'll find out over the next 55 days.