And I believe he called the protesters communists and sexual deviants as I understand the quote. But certainly there were people who tried to blame Governor Reagan for the violence inciting violence. Is this about command and control or is this about an opening a Pandora's Box?

DAVID GERGEN, CNN SENIOR POLITICAL ANALYST: It's about inciting and encouraging violence by a candidate, Ronald Reagan did (INAUDIBLE) I don't recall him ever inviting people to punch them to beat them up. HARLOW: Donald Trump says, I'm just telling them to fight back.

HARLOW: So Jeffrey Lord, I mean, to you David Gergen says, Trump bears moral responsibility for this. HARLOW: Or did you want to be Donald Trump come out and condemn any sort of violence and say, it's not OK? Well, first of all, he is not -- I mean, he has condemned violence, number one.

I mean, there is the argument to be made that Trump could have come out and said Chicago, I am so disappointed in what happened, this is unacceptable, period. But number two, these were thugs, this is exactly what they were doing. I mean, it was a pretty serious thing and the media of the day was all over Governor Reagan and blamed him for this. Was the media wrong, if they sent in the police and people got killed? (BEGIN VIDEO CLIP) HILLARY CLINTON (D), PRESIDENTIAL CANDIDATE: If you see a bully stand up to him.

I want you to know that I'm running for president to tear down all of the barriers that hold people back.

I want us to work together to build ladders of opportunity to empower every American so that every single person especially young people, have a chance to live up to their God given potential.

His argument, basically, is if you're strong, if you're passionate about your country and somebody disagrees with you at my rally, it's OK to beat them up. I think the candidate sets the tone are for his rallies, I think that's his responsibility.

If Donald Trump is not willing to renounce violence and call for peaceful rallies and stand up in front of the entire nation and do that at his rallies, then he bears moral responsibility for any violence that ensues.

GERGEN: Donald Trump has made the argument, I missed the good old days of when people acted up like this, they went out on a stretcher.

And we don't do that anymore because we've become so weak.

He said they had a Hillary Clinton rally just here and they had the same number of officers devoted. And so they are trying to make sure that when they go into this rally tonight that they can keep the peace and make sure that nothing happens like what we saw in Chicago last night.

But he did tell me yes, we are certainly aware of what happened last night in Chicago, what happened in St. And Poppy, I think the big question that will tell us whether or not we have a repeat of what happened last night in Chicago, is essentially do the protesters try to go inside. And essentially causes the Trump campaign to cancel it. Let's talk more about this as we wait for this Kansas City rally to begin with me now.

(CHEERS AND APPLAUSE) We got to knock down the economic barriers that stand in the way of people getting good jobs, with rising incomes. So, Poppy, imagine if the Donald Trump runs the board.