KARL: You have been very critical of the president's handling of ISIS. Some are out there, like Senator Graham, saying we should seasoned 10,000 U.S. ground troops right now into Iraq to help with this fight. Do you favor that?

WALKER: I think we shouldn't rule anything out. I think that's a big mistake this president has made here and elsewhere about saying how long we would go or how much we would invest.

KARL: I'm not talking about ruling it out. I'm saying, would you do that?

WALKER: No, I'm not arguing that's the first approach. I'd tell you three specific things I think we should do in Iraq. First, we should re-engage the strength of the American forces that are there. Once you do that, you empower the ally forces that are there in Iraq to reclaim the territory that ISIS has taken. And third, you just need to make sure you do it in a way that doesn't provide a safe haven, like in Syria as you push them out.