NPR logo Britney and Paris. And Obama?

Britney and Paris. And Obama?

A new ad for Sen. John McCain (R-AZ) analogizes the worldwide celebrity of Sen. Barack Obama (D-IL) to the fame enjoyed by Britney Spears and Paris Hilton. And it questions his ability to lead.

Hours later, the Obama campaign answered in kind:

Last night, pundits debated the efficacy of the ad. Has the McCain campaign gone negative?, they asked. Is there no turning back?

We'll talk about the effectiveness of negative political ads. Even if they're dirty, or wrong, do they work? What do you think.