Does the prospect of a long, drawn-out contest between Barack Obama and Hillary Clinton spell doom for the eventual nominee? A lot of people have a sinking feeling that it does. Kevin Drum makes the case for chilling out by reminding us that the internecine fighting could hardly get worse than it was in 1968:

If long, bitter, primary campaigns really destroy parties, then Humphrey should have lost the 1968 election by about 50 points. "Bitter" isn't even within an order of magnitude of describing what happened that year. And yet, even against that blood-soaked background, Humphrey barely lost.

So I say: chill out. Like a lot of people, I'm not very happy about the direction the Democratic campaign has taken, but the idea that it's going to wreck the eventual winner's chances in the fall seems pretty far fetched. It takes more than a few nasty exchanges to do that. And who knows? By keeping Dems in the spotlight, it might even help them. Stranger things have happened.

Maybe. Although it is hard to draw conclusions based on races like 1968 in which you saw a very substantial third party vote (indeed it strikes me as a bit odd that we're not seeing such a vote; McCain winning the nomination seems tailor-made for Ron Paul to run an appeal to anti-immigrant and anti-war sentiment). It is true, however, that political outcomes are mostly explained by the fundamentals -- demographics and objective events in the world -- and not by the candidates or the campaigns. On the other hand, a presidential election is fundamentally a zero-sum, high-stakes competition, so at the end of the day marginal impacts are very important even if they're rather small.

At any rate, consider this. Yesterday Josh Marshall had a complaint:

Let's note that Sen. McCain has decided to hang tough with his embrace of anti-Catholic, anti-Semitic Pastor John Hagee. And the major papers and cable news outlets have decided to give him a pass.

I've been Hagee-bashing since before it was cool, so this pisses me off, too. But realistically it's not the press and the cable networks that gave McCain a pass, it was Hillary Clinton and Barack Obama. They gave him a pass because, of course, they were arguing with each other. For a little while during the Wisconsin-Texas interregnum, Obama did pivot in the direction of McCain and it gave Clinton the opportunity to smack him over the head with a frying pan. I assume neither campaign is going to make that mistake again until this thing is actually wrapped up. But that means that there'll be nobody effectively pressing the media with anti-McCain talking points. It also means that Clinton will continue re-enforcing whatever good lines of attack McCain comes up with against Obama, and if McCain starts delivering good anti-Clinton lines, Obama will probably start re-enforcing those, too.

This kind of dynamic hardly guarantees defeat in November, but it's hard to see how it helps.