Asked about his support for liberal Republican Dede Scozzafava in the New York-23 special election, Newt Gingrich said on Fox last night:

GINGRICH: Well, there’s no question, on social policy, she’s a liberal Republican.

VAN SUSTEREN: On such as abortion?

GINGRICH: On such as abortion, gay marriage, which means that she’s about where Rudy Giuliani was when he became mayor. And yet Rudy Giuliani was a great mayor. And so this idea that we’re suddenly going to establish litmus tests, and all across the country, we’re going to purge the party of anybody who doesn’t agree with us 100 percent — that guarantees Obama’s reelection. That guarantees Pelosi is Speaker for life. I mean, I think that is a very destructive model for the Republican Party.

The problem is that Gingrich is making a valid point in general, but one that doesn’t apply in this specific instance. There’s no doubt that if you want to build a majority, you have to be willing to accept less conservative candidates in certain regions where a conservative has no chance of winning. As many problems as I have with Olympia Snowe and Susan Collins, I concede that it’s unrealistic to believe that we could get a genuine conservative Senator elected in Maine, which Obama won by 17 points. In the case of Giuliani, you were dealing with a city that hadn’t elected a Republican who remained a Republican in over 50 years. He was conservative on economic issues, and uniquely suited to deal with the most pressing problem facing the city — rampant crime. The only option was to support him, or allow David Dinkins to have another disastrous term as mayor.

But the New York Congressional race is entirely different. Scozzafava isn’t just a social liberal — she’s an economic liberal, too. She supports card check legislation that would allow labor unions to expand their ranks through intimidation. She called the cops on a conservative journalist who was asking her questions about her position on taxes. And there’s actually a conservative in the race who has a realistic chance of winning.

Gingrich made a clear mistake here. Maybe he privately realizes it, maybe he doesn’t. But his efforts to double down and explain his decision keep making him look sillier.