At least John McCain's new nastygram to Barack Obama isn't about sex-ed pedagogy or Paris Hilton similarities. This time, to McCain's credit, he's doing his character assasination on a major issue of the day--the war in Iraq, and Obama's 2007 vote against the GOP version of a measure to extend war funding. "Playing politics, risking lives," a suitably dismayed-sounding narrator intones. (Not mentioned: Obama voted for a Democratic measure that included war funding as well as a nonbinding call for withdrawal).

For the second time in a week, the spot also features a cameo from a Democratic supporter of Obama's. And not just any Democrat: It's his running mate, Joe Biden! Back in the primary season, Biden blasted Obama and Hillary Clinton for their votes. "They said they voted against the money to make a political point," Biden says in one clip, from a talk at the 2007 Iowa State Fair. In a second, more subdued appearance on "Meet the Press," Biden says "this is cutting off support that would save the lives of thousands of American troops." Echoing a standard GOP line, the finale declares Obama not ready to lead.

The spot will draw shrieks from Obama supporters who'll see it as another case of McCain implying that the candidate is treasonous--a devious and all-too-effective tactic that may well be McCain's last refuge as the campaign season ends.

But is it effective? I'm not so sure. For one thing, the first Biden quote--intended, I imagine, to portray Obama as perpetually focused on his own political advancement--managed, Biden-like, to undercut itself. If they were voting that way to simply send a message rather than to shape policy, Obama et al presumably a) assumed the funding would ultimately pass; and b) had a bigger policy message in mind than one senator's advancement, namely the idea that the Iraq war should end, an idea most Americans share. The second Biden quote is more effective, but by that point in the ad, after what by 30-second spot standards was a fairly complex discussion of legislative voting motivations, viewers are a little lost.

More importantly, the ad fails, as the earlier Clinton ad did as well, to place the very real Obama/Biden contrast front and center, instead burying it in a slam on Obama's loyalty, and not even adding a voice-over explanation along the lines of "even his own running mate thinks he's naive." There are only so many times McCain can go back to the rival-Democrat-cameo well, and this seems to me to represent a lost opportunity.

--Michael Schaffer