"Stop making these promises that we cannot pay for. Electoral campaigns are no longer won with promises!"

-- François Bayrou's message to Nicolas Sarkozy and Ségolène Royal last night on "I Have a Question For You."

Presidential candidate François Bayrou is running right down the middle of the road. The former professor from farming country has ridden a wave of disenchantment with conventional politicians and the traditional ideological divide. In a poll last year, a striking 69 percent of the French polled agreed with the phrase, "I have confidence in neither the left nor the right to govern the country."

That note of world-weariness among the French electorate has seen Bayrou position himself as a potential third man in this campaign. His poll numbers have risen steadily to 17 percent of the first round vote. Last night he promised to end the "perpetual war" between the Socialist and Gaullist UMP parties with a unity government assembled from like-minded members of the left and the right.

But, as a former education minister in two right-wing governments and head of a traditionally Gaullist UDF party, Bayrou's own promises tend to sound a little hollow. Both Royal and Sarkozy ironize about his centrist credentials. Last night, the UDF leader re-iterated his promise to consider naming a left-wing prime minister if elected. But critics charge that Bayrou will need right-wing support if he is to form a government and that his lefty PM nod is, in short, a vow he just couldn't keep.

The program on which he appeared last night, "I Have a Question For You," has had a big impact on the campaigns of his main competitors, who appeared in previous weeks. We'll have to wait for today's polls to see if Bayrou gets a bounce. But he's not as compelling a speaker as Sarkozy, Royal or, for that matter, Le Pen.

Part of Bayrou's rough-edged charm is a sort of warm cantankerousness. This the candidate who gained great attention in 2002 - and boosted a meager following -- after he hit a kid who he said was trying to steal his wallet on the campaign trail. That pugnacious Bayrou didn't play well in the touchy-feely audience-interview format last night. He was visibly awkward and uncomfortable as the host, news anchor Patrick Poivre d'Arvor, repeatedly advised him about where to look and even where to position his body.

It's hard to imagine Bayrou's performance convincing hesitant voters in a campaign where centrism is becoming a cliché, even for Le Pen. If Sarkozy and Royal don't make any big mistakes and Bayrou fails to perform better on the screen, his 19 percent showing in the most recent poll, taken before last night's program, could be his peak.

The ratings are suggestive: Royal got the highest, with 8.91 million viewers; Sarkozy got 8.24 million; Bayrou only garnered 6.68 million.

--Tracy McNicoll and Eric Pape

Photo of Bayrou by Jacques Brinon / AP