Senate: Dems Getting Hammered by Super PACS

In a tough reelection fight in Missouri, lefty Claire McCaskill defends against a huge influx of super PAC money. She's running a clever ad, but like many Dems, she's being outspent by outside groups.

Conservative and pro-business groups have outspent liberal groups by more than 4-to-1 in Missouri, where Sen. Claire McCaskill (D) faces a difficult reelection. Polls show her trailing or even with several Republican opponents.

Crossroads GPS has spent about $1.6 million, the U.S. Chamber of Commerce has spent $988,000 and the 60Plus Association has spent $481,000 on television advertising, according to Democratic sources who track media buys.

Of course, the ads against McCaskill, like this one from Crossroads GPS, are pretty effective as well.

Did you notice how the first ad, defending McCaskill, showed a production line worker going from one TV monitor to the next? The super PACS do take a template and use it in race after race - watch the attack on McCaskill become an attack on Sherrod Brown in Ohio.

While McCaskill has suffered $3.9 million in attacks, pro-Democratic groups have funded $887,000 in ads praising her record on veterans and other issues, according to Democratic media-tracking sources.