MORE BAD NEWS FOR CBS:

A handwriting expert says the two signatures on purported Texas National Guard memos aired by CBS News this week are not those of President Bush’s squadron commander, as asserted by “60 Minutes.”

Until now, press scrutiny of the memos supposedly written by the late Lt. Col. Jerry B. Killian focused on the finding that the documents were, in the opinion of experts, produced by computers not yet in use in the early 1970s.

Then there’s this: “Gary Killian said one paper with his father’s signature appears legitimate, but he said another — in which his father says he was under pressure to ‘sugar coat’ Bush’s performance — seems fake.” I’m no handwriting expert, but the signatures sure look different to me.

CBS needs to come clean by explaining where it got the documents (chain of custody matters!) and making its original (or, as it appears, its original copy”) available to independent experts.

Reader John MacDonald thinks that CBS will go on the offensive, instead of answering questions: “Wait for them to do hard hitting analysis of the blogosphere in order to diminish its credibility.”

Well, they can try that, but it won’t help them. Indeed, the more you disparage the blogosphere as a bunch of guys in pajamas, the more embarrassing it is when they show you up. (No word yet on what Pajama Pundit thinks about his newfound fame. . . .) [LATER: My mistake — Pajama Pundit is a she, not a he. This revelation will no doubt produce additional traffic.]

And as I’ve said before even if — as seems increasingly unlikely — these documents were to turn out to be real, it now seems pretty clear that CBS was gravely irresponsible in taking these documents public and presenting them as unimpeachably accurate without looking at them more closely first. No amount of after-the-fact lawyering will change that.