The third and final presidential debate between Barack Obama and John McCain took place one year ago last week—Oct. 15, 2008. It's worth recalling that encounter now for its remarkable revelations of things to come.

The debate was marked by heated charges from McCain and cool responses from Obama—what The New York Times the next day called his "unflappable demeanor."

Running out of time and depleted of character, McCain strained in the debate to disqualify his young rival with attacks on Obama's character. The highlight, or lowlight, of this exercise was the Republican nominee's decision to mimic his hapless running mate by tying Obama to "a washed-up old terrorist" named William Ayers. Four decades before, Ayers had been a member of the violent Weather Underground; now he was a professor living in Obama's Chicago neighborhood.

For Americans fearful of financial collapse, McCain's focus was stunningly out of touch. Obama deftly dissed Ayers, condemning the "despicable acts" of this "radical domestic group" while noting that he himself was just 8 years old at the time the acts were committed. For good measure, he added that his principal association with Ayers was serving with him on a nonprofit board funded by "one of Ronald Reagan's ... close friends."

Obama's nonchalance left McCain seething. As the GOP's fading hopeful pressed on, his scattershot assault turned to ACORN, an organization most Americans had never heard of—and still haven't. The Democratic nominee brushed his elder aside and rebuked him: The fact that this has become "so important" to you, Obama told McCain, "says more about your campaign than it does about me."

But Obama's response actually said a great deal about him. The pre-debate hype had been rife with speculation about whether McCain would take the gloves off; when McCain did, Obama side-stepped his jabs and held to his own chosen ground—the economy and health care. He refused to be distracted or dragged into the muck.

This was the same Obama who, in his first days in office, ignored the alternating alarms of the daily news cycle and soon signed into law the largest stimulus package in the history of any nation on earth. He held to his economic course in the face of those on the left who argued that he was doing too little and those on the right who trotted out old shibboleths about big government and big spending.

The day of the third debate marked one of the Dow's worst falls; exactly one year later, the Dow climbed above 10,000. Soon, Obama will be able to report that job losses have ended and job growth has resumed. Obama refused to be pushed off the path to a new prosperity; and if he has to adjust along the way, he'll display the same equanimity with which he disposed of McCain's modern-day McCarthyism.

The debate previewed not only Obama's skill and temperament, but the nature of the Republican opposition. It wasn't a long way from suggesting that Obama had associated with terrorists to smearing him as a "socialist" or "communist"—or as the "birthers" would put it, someone who is literally un-American. McCain himself actually took on a supporter for calling Obama "an Arab." But in echoing the darker impulses of the Republican base that night, he foreshadowed the dominant nature of today's GOP opposition—personal, bitter, and almost entirely negative.

McCain also used the debate to trot out Joe the Plumber, who was mentioned 24 times, more than any other subject. Joe pointed toward the rise of the stunt-ridden, misinformed and disinforming populism that twisted the national debate this past summer. Indeed, Joe set the table for the tea parties of August 2009.

Tea party petulance led some to complain that Obama had waited too long to act, or that he should have sent to the Congress legislation drafted in the White House and, Clinton-like, simply ordered its passage. This represented more instant analysis—or panic—to which the president refused to yield. Instead, he bided his time until he determined the moment was right to assume center stage—without elbowing aside senior legislators and jeopardizing the margin needed for victory.

McCain's reluctant deployment of the politics of personal destruction in the third debate reflected another reality, then and now: that Republicans resort to attacks because they lack answers.

When Bob Schieffer, the debate moderator, asked if the candidates would give up any of their proposals due to the economic crisis, McCain sounded befuddled and formulaic. He cited his "new" economic plan (though it was far from clear he'd had an "old" one) before lurching into ideological dogma: he favored an across-the-board federal spending cut. It was a no-brain non-starter, a position that even Dick Cheney had dismissed as "Hoover economics."

Yet throughout 2009, congressional Republicans embraced it, standing almost unanimously against the economic recovery plan and urging spending cuts that would have deepened and prolonged the downturn. When the latest budget report revealed that the deficit was $200 billion to $400 billion lower than previously forecast—in part because the feds had rescued the financial sector—the House GOP leader demanded that the government "stop spending taxpayers' money we don't have." It was an easy invocation of economic myth; if actually adopted, his policy would reverse the recovery and push unemployment toward levels last seen in the 1930s.

Similarly, the GOP health-care plan is ... Quick—can anyone describe it? Empty of ideas, full of grotesque fury about nonexistent "death panels," is it any wonder the GOP has a favorable rating of 24 percent in the latest Pew poll?

As health-care legislation churns toward completion—with Obama steady in the face of pressure and controversy—it becomes more evident each day that he will be the last president who has to fight for national health reform.

The final McCain-Obama debate now seems deep in the past. But it proved to be a reliable prologue and predictor. The attacks on Obama's character only showed the strength of his character. And the ugliness of those attacks, combined with the emptiness of the Republican "ideas" expressed by McCain, foretold the character of a political party that does little but seethe and sputter as history moves on.