For the presidential candidates, one of the big benefits of the current campaign finance system is that the super PACs backing them - which unlike the campaigns, can accept unlimited donations - can run attack ads on their behalf.
Throughout the campaign, Mitt Romney's well-funded super PAC, Restore our Future, has been fiercely attacking Romney's rivals in ads that helped Romney secure wins in key states like Ohio and Michigan. Since Romney doesn't have to publicly approve the messages - super PACs are technically independent of the campaigns, though they are often run by the candidates' former staffers - he was largely inoculated from voter anger for running the attack ads in the first place.
There are signs, however, that the Romney campaign is increasingly willing to do its own dirty work. The campaign released a new ad in Illinois, "Wrong Choice," which says Rick Santorum is unelectable and is weak when it comes to handling the economy. (Watch at left.) At one point, an announcer says of Santorum: "His plan? Economic illiteracy. Inexcusable. The worst idea of any GOP candidate. Rick Santorum - another economic lightweight."
How does the spot end? "I'm Mitt Romney and I approve this message."
Meanwhile, Campaign Media Analysis Group points CBS News to an even harsher radio ad Romney is running in the Saint Louis market that questions Santorum's electability. (While Saint Louis is in Missouri, its market extends into Illinois, where voters go to the polls Tuesday.)
Says an announcer: "Is Rick Santorum electable? Remember his last Senate race?" The spot then just cuts to audio of CBS News journalists discussing Santorum's landslide Senate reelection loss to Democrat Bob Casey in 2006, with Bob Schieffer noting that independents broke for Casey. (Listen here.)
"By historic margins, Pennsylvania voters rejected Rick Santorum," says the announcer. "Why? Santorum voted repeatedly to raise his own pay. Voted with big labor against right-to-work. Voted for billions in wasteful earmarks - even the bridge to nowhere. In 2006, Santorum took more special interest money than anyone. Santorum even voted to confirm liberal judge Sotomayor. If his own state didn't trust him, why should Illinois?"
The spot ends with this: "I'm Mitt Romney, I'm running for president, and I approve this message."
This isn't to say that Restore our Future is staying out of Illinois, where polls show Romney with a small lead. The Washington Post reports that the super PAC has spent $2.4 million in television ads in the state over the past two weeks, while Romney is spending more than $1 million this week; Santorum and the super PAC backing him are reportedly only spending a little more than $500,000. But it is interesting that Romney is showing a willingness in Illinois to put his name on at least some of the attacks.