Larry Kudlow, financial guru, writing for the National Review, on May 21, 2008:

One of the things we’ve learned during the Democratic primary battle is that Hillary’s victories are bullish for stocks and Obama’s wins are bearish.

The clearest example was Hillary’s massive West Virginia victory. Stocks opened strong the following day. But after Obama’s big North Carolina win, a night he nearly carried Indiana, stocks opened way down.

Even though Hillary clocked Obama in Kentucky, since Obama took Oregon convincingly, he really carried last night’s elections and now stands on the verge of gaining the Democratic nomination. Not surprisingly, stocks opened down 80 points this morning.

Markets don’t like Obama.

Let's go to the videotape. How did the market like the conventions?

11,628.06 - Dow enjoys a nice bump and closes up on 8/22, the last trading day before the Democratic convention.

11,543,96 - Dow Jones index at the close of 8/29, the day following the end of the Dem convention, and also the last trading day before the GOP event. I guess the markets still don't like Obama all that much, because the Dow had ups and downs, but ultimately dropped over the course of the festivities in Denver, ending in the red thanks to a 171-point drop the day after Obama's speech.

Now on to St. Paul ...

11,220.96 - Dow Jones at the close on 9/5, the day after the GOP convention ends. Stocks did manage a 16-point gain following Day 1, which had featured cancelled prime-time coverage, a speech by Laura Bush, and also the relief that Gustav had done less damage than feared.
     Otherwise, the big day was a 314-point loss the day after speeches by Huckabee, Romney, Giuliani, and Palin.

So in the immortal words of Richard Dawson, "Survey SAID ..."

Net Dow Jones loss during Democratic convention: 84 points.
Net Dow Jones loss during Republican convention: 323 points.

What are we to think? We are left with only two real possibilities:

a)  Mr. Kudlow was correct. However, the financial markets dislike John McCain 284% more than they dislike Barack Obama.
b)  Mr. Kudlow, allegedly a Very Serious Person with a career in studying how the markets operate, knew that he was ignoring the difference between causation and correlation, and was fully aware that his "professional" assessment was in fact pundit malpractice and Total, Utter Crap.

I'm fine either way. But in lieu of a definitive answer, I suppose I'm happiest keeping both answers in a simultaneous state of "possibly true." After all, current pet status aside, I have a long history as a cat person.