While high school debate judges might be willing to declare winners and losers, no one has come up with a truly foolproof and objective way to determine which candidate wins or loses a presidential debate.
That judgment merely morphs into a national debate of its own, with members of both camps spinning like tops to create the rosiest picture of their candidate's performance. Pundits and various experts then weigh in with their opinions.
We also get the verdict of voters who have watched the debates in closed rooms while working dials that tell whether they approve of disapprove of what the candidates are saying. And eventually, we get broader polls of voters declaring which candidate they thought won the debate.
But ultimately, that judgment is subjective, a matter of personal taste and political inclination. And the results might not even translate into votes on election day
We suspect that the verdict at the end of Friday's presidential debate between Democrat Barack Obama and Republican John McCain depended largely on which candidate voters supported at the beginning of the debate. Most Obama voters no doubt declared him the winner; most McCain voters anointed him the victor -- and it is doubtful that many voters changed their minds on the basis of this first debate alone.
Nonetheless, the debate could have an impact. It might make undecideds more or less reluctant to support one of the candidates. The answers or the demeanor of the candidates might have swayed some voters. And this debate could have created expectations about the next one.
Obama and McCain will meet for two more debates. The Oct. 7 debate will feature a town-hall format, while the final debate on Oct. 15 will focus on domestic policy.
But of more immediate interest is Thursday's one and only vice presidential debate between Democratic Sen. Joe Biden and Republican Gov. Sarah Palin. It's safe to say that, with so little exposure of Palin to the voting public, curiosity about this debate is high.
Palin's one advantage -- and it could be significant -- is that expectations for her performance will be low. Despite being pushed to the background by the battle over the congressional bailout, she had a disastrous week on the campaign trail.
Her interview with Katie Couric, the CBS news anchor, was particularly calamitous. While reaction from Democrats has generally been muted, several conservative commentators have been virulent. One of them, Kathleen Parker, urged Palin to resign from the ticket for the good of her party and the nation.
This has put the Democrats in the ironic position of trying to build up her credentials before the debate so Biden doesn't fall victim to sky-high expectations that he will stomp Palin into dust. And Biden must be extra careful to curb his tendency to run off at the mouth or to say something patronizing to Palin, who no doubt is praying for him to do both.
If Palin can score one good shot that gets played over and over again on the debate postmortems, she might come out ahead. That, after all, is how debates are won.
Or not. As noted, it all comes down to personal judgment, and this debate is no exception.
Judging who won the presidential debate always comes down to subjective view.