MILWAUKEE — On Wisconsin TV, Rick Santorum is getting pummeled as someone who doesn't understand the economy. On the radio, he's portrayed as squishy on funding for women's health care provider Planned Parenthood. In mailings, Santorum has "crazy ideas" that should be rejected in the GOP presidential primary in Wisconsin next week.

Yet again, Santorum finds himself on the short end of a lopsided ad battle with rival Mitt Romney and his deep-pocketed allies.

Santorum and his allies are calling the prospect of a Romney nomination a "disaster," but their counterpunches aren't landing with the same power.

Wisconsin's primary is deemed the most competitive of Tuesday's three elections, drawing far more interest than races in Maryland and Washington, D.C. That's translated into nearly $4 million in ad spending in Wisconsin so far.