You’d think the David Letterman-John McCain mini-feud would have blown over after a day, with both sides having better things to do (McCain had an economy to fix, Dave had to interview Paris Hilton), but on Thursday, neither side was shutting up about it. On the candidate’s side, his spokesperson Nicolle Wallace went on NBC’s Today and claimed the senator had bowed out of the Late Show at the last minute because he “felt this wasn’t a night for comedy.” Which was not the false excuse McCain had given Letterman. He’d told Dave he needed to fly to Washington right away to help solve the economic crisis, but he actually remained in New York until the next day and had been getting his face made up for an interview with Katie Couric during the Letterman taping he’d skipped, as Dave revealed via live feed. For his part, Letterman continued zinging McCain for weaseling out on him on a way that seemed inconsistent with his straight-talking war hero reputation. (Watch the meat of Letterman’s mean but funny diatribe here.) Dave even brought up McCain’s snub in passing during his chat with Hilton, who mentioned having been dissed by McCain herself.

Meanwhile, the fallout continued. Reaction was apparently mixed at CBS; Letterman employee Craig Ferguson backed his boss in this Late Late Show monologue, while CBS News staffers were reportedly livid that Letterman had embarrassed McCain (and, by proxy, Couric) by hijacking their feed. More than one pundit has suggested (here and here, for instance) that Dave’s continued lampooning of McCain could have a real-world political effect; not that Dave’s rants will persuade voters to pull the lever for Obama, but they could make voters see McCain in a less flattering light. A more cynical view suggests that Letterman will keep milking this feud for as long as he can, as he did his one-sided feud with Oprah, culminating in an eventual conciliatory visit from the senator which Letterman and CBS will hype for ratings, after which all will be forgiven, and Dave will go back to making jokes about George W. Bush’s stupidity and Bill Clinton’s libido (still comedy gold, even all these years later).

What do you think, PW-ers? Will Letterman’s continued pounding have an effect on potential McCain voters? Is he just drawing this disagreement out for ratings’ sake, or does he have a valid complaint? And if it is valid, has Dave gone from legitimately aggrieved to merely petty and petulant, or is his lampooning of the candidate still funny?