Economist and columnist Paul Krugman continues to rile his natural liberal allies by filing anti-Barack Obama screeds. On Monday he delivered the ultimate sanction, comparing Obama supporters to Clinton haters and even (gasp!) Richard Nixon in "Hate Springs Eternal."

In fact, these days even the Democratic Party seems to be turning into Nixonland.

The bitterness of the fight for the Democratic nomination is, on the face of it, bizarre. Both candidates still standing are smart and appealing. Both have progressive agendas (although I believe that Hillary Clinton is more serious about achieving universal health care, and that Barack Obama has staked out positions that will undermine his own efforts). Both have broad support among the party's grass roots and are favorably viewed by Democratic voters.

Supporters of each candidate should have no trouble rallying behind the other if he or she gets the nod.

Why, then, is there so much venom out there?

I won't try for fake evenhandedness here: most of the venom I see is coming from supporters of Mr. Obama, who want their hero or nobody. I'm not the first to point out that the Obama campaign seems dangerously close to becoming a cult of personality. We've already had that from the Bush administration -- remember Operation Flight Suit? We really don't want to go there again.

What's particularly saddening is the way many Obama supporters seem happy with the application of "Clinton rules" -- the term a number of observers use for the way pundits and some news organizations treat any action or statement by the Clintons, no matter how innocuous, as proof of evil intent.

The prime example of Clinton rules in the 1990s was the way the press covered Whitewater. A small, failed land deal became the basis of a multiyear, multimillion-dollar investigation, which never found any evidence of wrongdoing on the Clintons' part, yet the "scandal" became a symbol of the Clinton administration's alleged corruption.

Krugman is feeling the heat from Obama supporters and addresses it on his nytimes.com blog. He truly seems to think the media would prefer a Republican over a Democrat in the fall election:

It really makes me sad to see so many people get played by the media on this. If you prefer Obama, fine -- but the evil, race-card-playing Clinton campaign is no more real than Al Gore's claim that he invented the Internet.

And to Obama supporters, just remember: these people are not your friends. After they take down Hillary Clinton, if they can, your man will be next.

—Clay Waters is the director of Times Watch, an MRC project tracking the New York Times.