I find presidential debates painful to watch. The main reason is that isn’t they aren’t really debates, at least in the traditional sense of extended presentations of dueling arguments on a single, predetermined subject. When Abraham Lincoln confronted Stephen Douglas in 1858, the opening speaker spoke for an hour, was followed by a 90 minute response from his opponent, and then offered a 30 minute rebuttal (Lincoln and Douglas alternated speaking first). The encounter between Obama and Romney two weeks ago, by contrast, consisted of a series ten-minute segments in which the candidates answered questions posed by a moderator.

That format transforms ancient tradition of political rhetoric into a kind of dual interview. As such, it encourages the participants to pursue “zingers” and non-sequitur soundbites. There’s no question that Romney’s performance was more effective than Obama’s. Read in transcript, however, it develops no argument or vision.

There’s reason to expect that tomorrow’s encounter will be even more inane. One problem is the “townhall” format, in which voters ask impromptu questions. Leaving the choice of subjects to a moderator is bad enough: who cares what Jim Lehrer thinks is worth discussing? But soliciting questions from a relatively large audience almost guarantees incoherence.

A second problem is that participation in the townhall meeting will be limited to undecided voters. That means that they’ll be representative of only a tiny slice of the electorate: about 6% of likely voters, according to Reuters. Why should their questions have priority over other citizens?

It’s bad enough that citizens whose views reflect the vast majority of likely voters are excluded from the debate. What’s even worse is that undecideds are, speaking generally, the least informed and interested of likely voters. They haven’t made up their minds because they don’t know or care much about politics. As a result, they tend to be more concerned with character and manner than ideological commitments or specific policies.

The campaigns can’t be blamed for using debates to go after the few “sellable” voters who remain. Journalists and commentators, however, should not be shy about identifying the farcical character of the exercise. With the exception of the Nixon-Kennedy encounter in 1960, debates between the nominees became a regular feature of presidential politics only in 1976. Unless the candidates want to return to something resembling Lincoln and Douglas’s example, we’d be better off without them.