So we're still a little new to this Washington thing, and we're trying to understand: Why do Democrats who ran against the war in Iraq continue to vote to fund it? Why do Democrats who ran in favor of civil liberties vote for legislation that curtails them?

Let's think about how this works in the reality-based world.

Let's imagine, for a moment, that you want to buy a new car. You decide on a Prius; you tell everyone you know that you're getting a Prius; you even persuade a a friend -- he loves the environment as much as you do! -- to chip in some money to help you buy that Prius.

So you march yourself into the local car dealership, and you say to the fellow there that you've come to buy a Prius.

And he says no.

He says the only thing he'll sell you is a gargantuan, air-polluting, gas-guzzling, rolling-over-in-sharp-turns SUV. He says it will be better for you. "You know," he says, "if you buy the Prius, your neighbors are going to think you're a wimp."

What do you do?

You leave, right?

Maybe it means you don't get the car you want. But it also means that the dealer doesn't get your money and that you're not stuck buying something you don't want. If the dealer needs your money badly enough, he'll cave in eventually and sell you the car you want. If he doesn't, well, at least you can hold your head high as you drive your old beater around town.

That's how the story would have played out where we used to live. But it's different in Washington, apparently. If you're a Democratic member of Congress, and you walk into that dealership wanting to buy the Prius, and the guy there says that he'll only sell you a Gigantaur, you grumble for a moment -- you tell all your friends that it's unfair -- and then you give him your money and he hands you the keys to the Gigantaur.

As you drive off the lot, the dealer calls you a wimp. As you pull into your driveway, your friend calls you a liar. At least one of them is right, of course -- then, and six months later when you do it all over again.

Update: At least one Democrat gets it: Connecticut Sen. and presidential candidate Chris Dodd.