Political Web ads can be hard-hitting and entertaining (whether they are effective is a discussion for another day). But how can a campaign use popular rock songs? The answer, as the Charlie Crist found out, is they can't without permission.

Warner has smacked down Crist's recent salvo against Marco Rubio, asserting its copyright over a Talking Heads song "Road to Nowhere." If you try to pull up the Web ad, you'll see this:

Wonder what Crist supporter Mitch Bainwol, head of the Recording Industry of Association of America, thinks of this. Bainwol gave $1,000 to Crist's campaign in June.

Rubio's team might be careful, too, as they also have incorporated music into ads.