Is the left actually looney?

Peggy Noonan's description of the Democratic Party's problem with its "base" makes for an interesting read:

Democratic leaders in Washington are in a worse position than Republican leaders in Washington. Neither likes their base, really, and both think they are smarter. But the Democrats think, deep down, that their base is barking mad. The Republicans don't. They just think their base is a bore.

Members of the left have clearly gone to the extremes of what could be called dogmatic, and in many cases seem to suffer from some sort of delusional disorder.

But, it's a human failing that isn't confined to the left. While the folks who imagined a threat from black helicopters in the night years ago have disappeared from the political landscape, there are still people on the right wing of the political spectrum who cannot be shaken from belief in their own dogma by mere facts.

It's just more noticeable on the left today, since the Democrats have people like Pelosi, Reid and Dean acting as their public spokesmen.