Story highlights Donald Trump may not like super PACs, but one is coming to his defense in a very big way

The big buy comes as Trump finds himself trailing in Wisconsin

(CNN) Donald Trump may not like super PACs, but one is coming to his defense in a very big way.

The Great America PAC released an ad Thursday accusing his closest rival, Ted Cruz, of seeking to "give amnesty" to illegal immigrants and allow more Syrian refugees into the United States.

The ad appears aimed in part at attracting women voters, a liability of Trump's, by featuring a mother speaking directly into the camera saying she's backing Trump because of his national security and immigration views.

"Sure, I get some grief when I say I'm voting for Donald Trump. But you know what? I want to protect my family," the woman says, standing in front of her children in the kitchen. "We need to control our borders and stop letting in dangerous people. Trump will do that. And Ted Cruz? He wanted to let in more Syrian refuges and give amnesty to illegal immigrants. That won't protect my family. Donald Trump will."

The ad is part of a seven-figure ad buy that will run nationally and statewide in Wisconsin ahead of its critical primary next week, according to Jesse Benton, a spokesman for the group.

Read More