The final 90-minute debate between US presidential candidates Barack Obama and John McCain is set for tonight and, as a result, undecided voters are getting a lot of attention from every corner of the journalism industry, from cable networks like CNN to daily newspapers like The Des Moines Register.

The idea is to track how these undecided voters react to whatever is said tonight, and to then translate those reactions into some semblance of a performance grade for each candidate. Interesting as always, I suppose, but, in my opinion, it's hardly worth the time and effort.

The better story — the one I want to hear — is how anyone informed enough to even volunteer for an undecided-voter focus group could possibly be undecided at this point in the campaign.

We've been on this bus for nearly two years — Obama declared in Feb. 2007 and McCain announced in April 2007. On top of that, our nation is in the midst of what will likely turn out to be the worst financial disaster of any of our lifetimes, a problem to which each candidate has taken an approach opposite the other. In that and many other ways, these candidates are very different. Pick your cliché — apples and oranges, hot and cold, whatever — the choice is clear. So how could anyone who's been paying attention still be undecided?

Unless they're not really undecided.

Most Americans would surely defend any voter's right to alter his or her choice right up until their ballot is marked and sealed. But a voter who changes his or her mind is hardly an "undecided" voter. That's a "decided" voter acting within his or her right to re-decide.

At this stage it's just plain common sense to question either the honesty, or the analytical skills, of anyone who claims to be truly undecided.

I'm not saying there aren't undecided registered voters out there somewhere. I've no doubt they're there, probably far outside the reach of TV and radio waves, and nowhere near an Internet connection. But even if we rounded a bunch of them up, verified their undecidedness, and tied them down to watch tonight's debate, of what meaningful use would their opinions be?

We might as well ask them to name their favorite Beatle.