Until Wednesday night, it looked as though the US election in November might not be such a close call after all. Barack Obama was pulling ahead; a string of gaffes appeared to have confirmed his Republican challenger as out of touch, willing to say anything to get elected, simply not up to the job. Now, however, with Mitt Romney hailed the conclusive winner of the first of three televised debates, the race might just be back on.

There are any number of possible explanations for the President's rather colourless performance. Perhaps he was trying to avoid being aggressive. Perhaps he was keeping his powder dry for the two debates to come. Perhaps he was just having a bad day. In any event, it does not matter. The fact remains that so lacklustre a display looks too much like complacency for comfort, and it is a gift to those critics who claim Mr Obama's cool-as-a-cucumber style is a mark of arrogance.

If the President did not appear to be firing on all cylinders, the same could hardly be said of Mr Romney. Here was neither an extremist in hock to the Tea Party, nor a craven flip-flopper, nor a muddled chancer vastly over-reaching himself. Forceful without being overbearing, passionate without being crazy, coherent without being dogmatic; here was a man very much in command of his brief and, for the first time, a real contender for the White House.

Mr Romney drew heavily on his time as the Governor of Massachusetts. He even managed to turn his controversial business background into a plus, using it to add authority to a message relentlessly focused on jobs. Perhaps most effectively, he peppered his arguments with the experiences of ordinary people he has met on the campaign trail. An elementary presentational tactic, perhaps; but no less effective for that. Even more so given that Mr Obama tended to refer to studies and statistics rather than to real people. Once again, the sense was of a President who rarely steps outside the Oval Office versus a challenger fresh from the stump.

Perhaps as striking as the candidates' relative performances was the high quality of their debate. There was little mud-slinging, no personal attack, and few of the one-line "zingers" so beloved by strategists. What there was, was lots of serious policy debate. Indeed, if televised head-to-heads needed any vindication, here it was. For 90 minutes, American voters got the full works: an articulate, highly coherent contest between two – perhaps surprisingly – well-matched figures, on tax policy, on deficit reduction, on healthcare reform.

The substance, of course, is another matter. In all likelihood, the armies of fact-checkers now crawling over every word will blow holes in many of the claims and counterclaims in the days ahead. Meanwhile, Mr Romney, for all his convincing style, failed to offer an alternative to the healthcare and banking reforms he wants to replace. Similarly, the President failed to make the knockout case for Obamacare. And neither candidate tackled America's looming "fiscal cliff" in any detail. That said, the welcome impression of two serious candidates, offering genuinely competing answers to their country's problems, remains.

Whether Mr Romney's success translates into a bounce in the opinion polls remains to be seen. But Mr Obama should certainly be worried: his nascent lead in crucial swing states would not take much eroding. Either way, the President needs to raise his game. But that is no bad thing. The US faces difficult decisions; it is in all our interests that there is a real debate about what they are and how they are made.