Voters head to the polls today in Wisconsin, Maryland and Washington, D.C. While newly released opinion surveys suggest Mitt Romney will sweep all three primaries, his chief rival Rick Santorum has vowed to stay in the race until at least May, when he hopes to pick up victories in Texas, Arkansas, Kentucky and North Carolina. On Monday, Santorum released a new ad comparing Romney to President Obama. Throughout most of the ad, a photo of Obama’s face appears on the screen.

Rick Santorum: “I’m Rick Santorum, and I approved this message.”

Speaker: “What if I told you this man’s big government-mandating healthcare included $50 abortions and killed thousands of jobs? Would you ever vote for him? What if I told you he supported radical environmental job-killing cap-and-trade and the Wall Street bailouts? And what if I told you he dramatically raised taxes and stuck taxpayers with a $1 billion shortfall? One more thing. What if I told you the man I’m talking about isn’t him [Obama]? It’s him [Romney].”

That Rick Santorum ad ends with President Obama’s face morphing into Mitt Romney’s.