Victor Davis Hanson

The trick for Obama in the second outing was to show Americans that the first debate had been a freakish anomaly -- and Romney really was the caricature that had been depicted during months of negative ads. Yet if Obama won tactically, he lost strategically through his combative demeanor and the very fact that Romney was not only still standing after three cumulative hours of head-to-head jousting, but gaining even more ground in the polls.

This week, the third and final debate offered Obama a last opportunity to convince the American people that at least on matters of foreign policy, Romney was either dangerous or ill-informed. That challenge also ensured that Obama would have to crowd into the final 90 minutes near-constant attacks to crack the calm Romney facade. Even or ahead in the polls, all Romney had to do in response was for a third time keep acting presidential and prove that his earlier displays of composure and competence were no flukes -- a no-brainer strategy clear to anyone who had followed the first two debates.

That is precisely what Romney pulled off. As in the second debate, Obama might have done well enough to come away with a tie or even a narrow win on points, but he probably didn't fare well enough to reverse his slide in the polls. If Obama sought to shatter Romney's image as a compassionate and competent captain of industry, he more likely damaged his own once carefully crafted image as a nice guy.

So what did we learn from nearly five hours of verbal gymnastics?

The image of competency and composure that Romney projected in the first debate was not altered by the second and has been confirmed by the third.

Presidential debates really do matter, and a few hours of engagement with Romney may have cost Obama what he had tried to ensure through six months of attack-dog campaigning. And so in the last 10 days of the campaign, Obama will have to return to negative advertising -- a last hope to achieve through personal attacks what he couldn't accomplish through public persuasion.

If voters conclude that Obama is desperate to demonize Romney in a way he could not in the fair match of the public debates, then Obama will probably lose the election.

Victor Davis Hanson

Victor Davis Hanson is a classicist and historian at the Hoover Institution, Stanford University, and a recipient of the 2007 National Humanities Medal.