Amy Walter quotes:

If you're Chris Christie, who is governor of New Jersey, a state that obviously was impacted by 9/11, this gives you an opportunity to talk about how, as governor, you had to deal with terrorism and security issues.

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

When Jeb Bush came on the shows and couldn't answer questions about Iraq, and when he looked like he was unsteady, it absolutely solidified the concerns that they had had all along about his skills.

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

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 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.

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.

The real problem with Donald Trump is, if you engage him, it will only make things worse. It's like - it's a little bit what you were taught as a kid to not engage the bully, because they will continue to pick on you.