[Kristen Holmes, Cnn Correspondent:] I understand I haven't gotten the support of all the Republicans, of all people in my own party there. But that being said, he did take a step to quell those concerns yesterday by, as you mentioned, endorsing Speaker Ryan. He had upset several party leaders she he said earlier in the week that he wasn't sure he was ready to endorse Speaker Ryan. In addition to that he also endorsed Senator John McCain from Arizona and Senator Kelly Ayotte from here in New Hampshire where we are right now. And so we'll see how all of this message of unity moving forward, how that affects the party in the coming days, really. And I should mention, Fred, we did reach out to Senator Kelly Ayotte's office to see if she would be here with Donald Trump at this rally in New Hampshire. We have not heard back yet. We're still waiting on that.
[Fredricka Whitfield, Cnn Anchor:] All right, Kristen Holmes, thank you so much. Keep us posted, appreciate it. I want to bring in Julian Zelizer, a historian and professor at Princeton University. All right, so, given you are a historian, let's start with Trump quoting Ronald Reagan. Is he trying to appeal to traditional Republicans? Is he trying to appeal to an audience that hasn't necessarily shown him a whole lot of love?
[Julian Zelizer, Historian/professor, Princeton University:] Well, it is not clear. What Reagan did was first to convince all the different factions in the conservative movement that he was the best bet for the Republican Party, that he was the best bet to actually create a coalition. And I don't think everyone in the Republican Party feels that way right now. And Reagan worked hard not to alienate different Republican groups. So in some ways the reverse of what we're seeing with Donald Trump. He reached out to show that he would support a very broad agenda and he avoided the kind of polarizing remarks within the Republican Party that could have hurt him.
[Whitfield:] And Trump waited until campaign stop in Wisconsin, Paul Ryan's home state, to finally endorse him, just days ago saying, quote "He wasn't there yet" when asked about a Ryan endorsement. So is this pressure from the establishment from the RNC, the GOP saying you have got to do this? Or is he having second thoughts?
[Zelizer:] I'm sure there is a lot of pressure, especially for Republicans who have endorsed him despite what they privately want to do. And to have him then attack is really hard for a lot of Republicans to take. So I'm sure the pressure has intensified. What is not clear is if Donald Trump will continue on listen. We've seen throughout the campaign he is his own person. He can be very erratic and he can be very tough when someone tries to restrain him. So my guess is this won't last long and we're going to more internal party conflict in the coming weeks.
[Whitfield:] And these endorsements, it is coming at a time when the Trump campaign has been embroiled in several controversies, falling poll numbers. There has even been talk, loose talk that has been published about whether Trump is going to drop out or whether he would be replaced by the establishment. Is all of that just talk?
[Zelizer:] No, it's not just talk. This is an unusual campaign. We haven't seen anything like this. I think that's fair to say. And so there is an element where many Republicans, Democrats don't know what's coming next. And they don't have a full gauge of how Donald Trump thinks. So I think there are many people who feel not because of pressure but because of becoming frustrated with the processing, sensing that he might who's very badly, that he actually steps out of this whole race. So I think it is loose talk, but I think there's a basis for it. And that's what has many people in both parties nervous about what comes in the weeks ahead.
[Whitfield:] Yes, and nervous about whether that's the October surprise.
[Zelizer:] Right, that would be quite a surprise to lose a candidate a month out.
[Whitfield:] Again, we don't know anything, just a whole lot of chatter out there. Julian Zelizer, thank you so much, appreciate it.
[Zelizer:] Thank you.
[Whitfield:] All right, it's not just New Hampshire. Colorado is also a key battleground state, one which Donald Trump has called a must-win in his race for the White House. CNN's Kyung Lah takes a closer look at the different strategies of the two campaigns.
[Kyung Lah, Cnn Correspondent:] In the battleground state of Colorado, the ground war.
[Unidentified Male:] I'm getting people registered to vote.
[Lah:] Taking aim with real and augmented and retail politics. Clinton campaign workers playing "Pokemon Go" to register potential voters, and using other attention getting draws. A cello?
[Anthony Carlson, Colorado Democratic Party Regional Organizing Director:] A cello. You have to be unique, especially in a battleground state like Colorado where the stakes are so high.
[Lah:] Battleground Colorado twice elected Republican George W. Bush, then gave Barack Obama back-to-back victories. This year the state is showing signs of leaning Democratic. Some recent polls give Hillary Clinton a double digit lead. Another potential advantage, since 2012 Democrats have registered more voters than Republicans. And the ranks of Latino voters continues to grow up to 15.3 percent, higher than the national average. And 14 Clinton campaign offices are up and running in the state, hundreds of workers are on the payroll, the operation expected to triple by early October.
[Emmy Ruiz, Colorado State Director, Hillary For America:] We're not going to take anything for granted. For us our ground game is critical.
[Lah:] Democrats have spent $5.6 million on Colorado TV ads while Trump supporters have spent $232,000. The Clinton camp now polling TV ads, saying Trump isn't on the air waves or, frankly, on the pavement. Are you seeing the Trump operation out there?
[Ruiz:] No, I haven't.
[Lah:] The Trump plan in Colorado is far different. Yes, there are some workers knocking on doors, but only a handful are on the payroll, most are volunteers. The Trump campaign has just five offices, relying instead on an extensive Republican national state and local network in place since 2013. The campaign is not worried about being outgunned in the traditional ground game.
[Robert Blaha, Chairman, Trump Campaign In Colorado:] Her game plan is the same old tired worn out paradigm we've seen for years and years and years. Trump brings a brand-new level of energy. Colorado will be decided in large by a group of people in the middle of America.
[Lah:] In Colorado, more than one third of voters are registered independents like Marc Sabin. He sports Trump.
[Marc Sabin, Independent Voter:] I will do it as an independent. So I will contribute directly to Donald Trump. I do not contribute to the
[Gop. Lah:] Loyalty to Trump, not party, and x-factor not lost on both sides. And with both candidates having high unfavorability numbers, it's leaving some independent voters uncertain of which way they'll go in November.
[Cara Miller, Independent Voter:] I'm not sure I want either of them as president.
[Lah:] So how are you going to decide, then?
[Miller:] I don't know. I guess the lesser of two evils.
[Whitfield:] All right, our thanks to Kyung Lah for that report in Colorado. Just a reminder, don't miss "State of the Union" tomorrow. Our Jake Tapper sits down with former GOP presidential candidate and Ohio Governor John Kasich. It all starts tomorrow morning at 9:00 right here on CNN. Coming up, aerial mosquito spraying wraps up in south Florida. Next, we'll take you live to Miami and show you what else is being done to prevent a larger spread of the virus.