Every day and in every way, David Letterman looks creepier and creepier…

• Some have been defending Letterman by saying he broke it off with Stephanie Birkitt before his son was born. As if living with Regina Lasko since 2001 doesn’t constitute some sort of commitment. Besides, evidence is (ahem) mounting that the relationship with Birkitt was ongoing until recently. First an Access Hollywood producer had an odd encounter with the two of them alone in public in 2005. Now, that could be passed off as “Just a couple of good buddies who definitely weren’t still having sex, the guy’s got a kid with his longtime live-in girlfriend, leave him alone.” But then there’s this:

Pretty former “Late Show” staffer Stephanie Birkitt revealed in her diary that she continued having sex with boss David Letterman even after moving in with her CBS-producer boyfriend, who later allegedly tried to extort him over the affair, sources told The Post yesterday.

Letterman and Birkitt enjoyed romantic hikes last fall at his sprawling ranch in eastern Montana — where he was married in March — while her boyfriend, “48 Hours Mystery” producer Robert “Joe” Halderman, stayed home in Connecticut, the sources said.

I dunno, New York Post… “Pretty”? And this is in addition to Letterman paying for her law school and letting her watch his kid. We’re supposed to believe that Lasko knew about all this and had no problem with the whole arrangement? And if so, that makes it okay?

• Tracy Clark-Flory at Salon.com asks, “Why aren’t feminists mad at Letterman?” Maybe because their ideology is more important to them than their principles? They both hate all the same people? Just a theory.
• Not having learned their lesson with Roman Polanski: Stars Stand by David Letterman
• If you still doubt the sincerity of Letterman’s apology to the Palins a few months back, you’re right.
• Lest we forget the other major sleazoid in this story, Letterman’s blackmailer Robert Haldeman seems to have crafted a unique defense for his attempt at extortion. As his lawyer says:

“Look at the fact that there was a $2 million check. In the history of extortion, I don’t think there’s been a single case where the alleged extortionist took a check in payment. It just doesn’t make any sense.”

So I think it’s going to go like this: Haldeman wasn’t really shaking down Letterman over the affair; he was selling Letterman his thinly fictionalized screenplay about the affair! Gotta give this guy points for chutzpah, at least.

• And just one question for Gawker’s Hamilton Nolan: If sex is no big deal, as you so subtly point out here and here, why has David Letterman spent at least a decade moralizing about other people’s sex lives? He’s made so much money looking down his nose at the human emotions and relationships of others, he could buy himself an island and fill it with interns. Heck, for all we know he has.

In Other Elderly Sex-Creep News: Roman Polanski ain’t goin’ noplace.