It's pretty simple.
Actually, I do think that is a fair point. I wish he would just state, “although this ad was in no way part of my campaign, I agree that political opponents should concentrate on issues and avoid attacks on family members.”
Of course, another poster asked me a question that proved another good point. Why do we start with the premise that this ad was an “attack on Trump’s wife?” I am not so sure that it was. That said, I do wish Cruz would come out with more strength and simply say that family members are off limits, so long as they are not part of the campaigns...
I will also admit that I don’t require it tho. He had nothing to do with the “tweet.” I think it is unfair to blame Cruz for it, just like I think it is unfair to blame Trump for the protesters causing havoc outside of his rallies.