The only problem with the "children of Reagan" line is it reminds you that Marco Rubio is the young candidate.

The difference there is that the [Donald] Trump number on change is so much larger than the lead that the other two have in their lanes. And that's going to be the challenge for those other two going forward. The other challenge for Marco Rubio, and this assumption that you're just going to get all those Bush and Kasich voters.

I think you still have a problem here when you're going and you're looking not just that Trump is winning, but he's winning in a broad swath of voters. It's not just that he's got this one lane, oh, he only wins when there's low turnout, he only wins when conservatives, he only wins in these kinds of states. He wins enough across a broad array.

The only problem with the "children of Reagan" line is it reminds you that Marco Rubio is the young candidate.

It was very clear, even from long before Donald Trump got in this race, when he would talk to Republicans, the number-one concern they had about Jeb Bush was whether he was too rusty for this, and whether he was going to be strong enough to stand up to Hillary Clinton.

Even on Ben Carson, he's not exactly steeped in housing policy, but his statements on the issue have also been very conservative.

The ones who are in the Senate have to have a position.