going to stick to substantive policy questions about the economy. if that's the case, ben carson doesn't need to be ready about the questions about his background, he needs to be ready for detailed questions about taxes, about the deficit, about spending, things he has not necessarily been comfortable going deep on. he'll have to do that tonight potentially. that's what ben carson should be looking out for. how about donald trump, the author of the art of the deal, we say, the art of the attack. so if donald trump does show up at this debate tonight intent on attacking ben carson, what will that sound like? well, trump has been previewing it in speeches before the debate. let's give you a taste of what donald trump has been saying about ben carson, when ben carson is not standing next to him. >> if you try and hit your mother over the head with a hammer, your poll numbers go up. you stab somebody, and the newspapers say you didn't do it! and you said, yes, i did! i did it!