GWEN IFILL: Now a look at the time-honored, but seemingly more frequent role of president as consoler in chief.
FORMER PRESIDENT GEORGE W. BUSH: America today is on bended knee in prayer for the people whose lives were lost here.
GWEN IFILL: They are the increasingly familiar moments of searing loss, when presidents give voice to the nation's grief.
FORMER PRESIDENT GEORGE W. BUSH: I can hear you. The rest of the world hears you. And the people ...
And the people who knocked these buildings down will hear all of us soon.
GWEN IFILL: Three days after 9/11, President George W. Bush stood on the rubble at Ground Zero in New York. Six years earlier, in April 1995, President Clinton comforted mourners in Oklahoma City after 186 people died in the bombing of the Alfred P. Murrah Federal Building.
PRESIDENT BILL CLINTON: We pledge to do all we can to help you heal the injured, to rebuild this city, and to bring to justice those who did this evil.
GWEN IFILL: The presidents act as stand-ins for a nation's anguish. In Jan. 1986, hours after the destruction of space shuttle Challenger, it fell to President Reagan to remember the seven astronauts killed that day.
FORMER PRESIDENT RONALD REAGAN: We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye, and slipped the surly bonds of Earth to such the face of God.
GWEN IFILL: And five days after President Kennedy was assassinated in Nov. 1963, the newly elevated President Lyndon Johnson went before a shaken Congress and country.
FORMER PRESIDENT LYNDON JOHNSON: No words are strong enough to express our determination to continue the forward thrust of America that he began.
GWEN IFILL: Yesterday, President Obama returned to the task, traveling to Moore, Okla., where 24 people died a week ago in a massive tornado.
PRESIDENT BARACK OBAMA: We know Moore is going to come back stronger from this tragedy. And I want folks affected throughout Oklahoma to know that we're going to be with you every step of the way.
GWEN IFILL: For Mr. Obama, it was only the latest in a series of somber occasions that have taken him from Colorado to Arizona to New Jersey to Boston.
So what can presidential words of comfort mean to victims of disaster, accidents and terrorism?
For that, we turn to presidential historian and NewsHour regular Michael Beschloss and Alexis Simendinger, White House correspondent for Real Clear Politics.
Welcome to you both.
MICHAEL BESCHLOSS, Presidential Historian: Thank you.
GWEN IFILL: So, Michael, is this now part of the job description to be consoler in chief?
MICHAEL BESCHLOSS: I think it is.
And it sure wasn't in the Constitution. And it's pretty recent, because for most of American history, we didn't have air travel, so it was hard for a president to get to a scene of a disaster. The federal government didn't do that much for emergencies like this. And you really didn't have TV, so this is really a creation of recent times.
GWEN IFILL: So, Alexis, the president doesn't have much choice but to show up at this point.
ALEXIS SIMENDINGER, White House Correspondent, Real Clear Politics: We are seeing now that most presidents feel that they are not just wanting to be there, but they're almost compelled to be there, that there's an expectation by the American people that he's the manager.
He's the uniter. He is representative of the federal government and all the help that is supposed to be coming from Washington in a world that expects to be almost risk-free now, that there's more benefits. There's lots more infrastructure inside the government, at the Department of Homeland Security, for instance, for natural disasters and catastrophes.
And there's an expectation in every community that the president and the entire executive branch with Congress will move to respond.
GWEN IFILL: Has this always been true? Has this always been the role?
MICHAEL BESCHLOSS: No, it really hasn't, because -- two points in time I like to think about, 1963, the submarine Thresher, nuclear submarine, sank off Cape Cod.
Over 120 -- or 129 people were killed. President Kennedy, even though he was in the Navy and this was his home state, Cape Cod, basically issued a statement. You would never see something like that nowadays. And LBJ, as we just saw in the taped package, 1967, the first Apollo crew perished in that horrible fire down at Cape Canaveral, and you didn't see the kind of thing you would see now, with the president going down, consoling families. He, sure, attended the funeral, but nothing like you would see today.
GWEN IFILL: So, what was the turning point?
MICHAEL BESCHLOSS: The turning point, I think, was really Ronald Reagan.
And probably the reason for that, as it oftentimes is in the history of a presidency, he was so good at it. The Challenger, we just saw a moment ago, that was the day he was supposed to give a State of the Union. He actually was only dimly aware of the shuttle flight. When he was told about it, he asked is, that the one with the teacher on it?
Everyone knew that this had a teacher in space. So he gave that speech that was so powerful that evening from the Oval Office that, ever since then, presidents are expected to do that.
GWEN IFILL: Is there a downside to this, toying too close to exploitation? For instance, in Tucson, when the president went and spoke after the shooting of Gabrielle Giffords, there was a little question about whether he was going to be doing a rah-rah thing for gun control.
ALEXIS SIMENDINGER: I think the impression that most presidents get very quickly is, it has to either be genuine or it has to sound genuine.
And it has to be less about them and much more about the people that they're seeing. As Michael was saying, presidents that are good at it get enormous benefits from it and -- and embraced by the American people.
Presidents who stumble, for instance, doing it, they teach presidents after them lessons.
MICHAEL BESCHLOSS: Especially if it looks too political.
ALEXIS SIMENDINGER: If it looks too political or it looks too late. And so we have seen that happen over time.
GWEN IFILL: Well, Katrina is a perfect example.
ALEXIS SIMENDINGER: Katrina is a perfect example.
President Bush was, as we know, absolutely clobbered by the American people, politically, in terms of -- as management, everything about Katrina and Rita.
MICHAEL BESCHLOSS: Absolutely.
ALEXIS SIMENDINGER: Congress -- and the laws changed after that to add a lot more to the whole process of managing crises.
MICHAEL BESCHLOSS: Yes.
And also no president is going to make that mistake again. They will err now on the side of going to every disaster conceivable, rather than suffer the fate of George Bush, who looked as if he was a little bit indifferent.
GWEN IFILL: How much of this is symbolism, and how much of is this about bringing cash on the barrelhead to the problem?
MICHAEL BESCHLOSS: Well, the symbolism -- symbolism is important. The founders did say that a president has to be both prime minister and chief of state.
But that's what monarchs do. But if you look through history and try to draw a correlation between, like, number of hours a president visits the scene of a disaster and amount of help that's effective from the federal government, virtually no correlation.
GWEN IFILL: What do you think about that?
ALEXIS SIMENDINGER: I think that there's a mix.
For one thing, the president doesn't have to be there. It happens now without him. He could be abroad, and all of this would happen. He signs ...
GWEN IFILL: All of what?
ALEXIS SIMENDINGER: All of the help, all of the infrastructure from FEMA, and -- the Federal Emergency Management Agency, all of that would happen without the president even if he were abroad.
But he signs the declaration. And those who have actually been comforted by a president or a first lady after a catastrophe have talked about how much it meant. For local media, we're listening to the president say, here's where you call if you need help. American Red Cross, here's what you do if you want to help, give money.
So, his bully pulpit, it is symbolism, yes, but it also has a practical impact too.
MICHAEL BESCHLOSS: And, also, he can learn from it. President Obama has said that, for instance, meeting with those victims of this violence taught him a lot, made him feel more passionate about trying to assure gun safety.
GWEN IFILL: And is it also one of those rare cases where government intervention is now welcomed, rather than, stay out of my business?
ALEXIS SIMENDINGER: Well, in this particular environment this month, does the president want to talk about how management and government is a good thing? Absolutely.
After the IRS problems that he's been experiencing, he wants to spread the word that government does good things, which is what he's talking about, and that management is -- in the executive branch is top notch at FEMA.
GWEN IFILL: Michael?
MICHAEL BESCHLOSS: Can't disagree with that.
But, you know, Lyndon Johnson, even at the moment of John Kennedy's assassination, you would think that would have been the most horrible thing for him to turn into politics, but he said, no memorial oration could more eloquently honor John Kennedy's memory than the earliest possible passage of his civil rights bill.
People thought it was very appropriate.
GWEN IFILL: So, even if you're Chris Christie or Mary Fallin, this doesn't necessarily -- I'm just being crass about this, I guess, talking about the politics -- it doesn't necessarily hurt you?
ALEXIS SIMENDINGER: Oh, it doesn't hurt you at all.
And the two governors -- we're talking about Republican governors. They are more than happy to see Washington, represented by the president of the United States, come to their communities.
GWEN IFILL: Alexis Simendinger, Michael Beschloss, thank you both so much.
MICHAEL BESCHLOSS: Thank you, Gwen.
GWEN IFILL: On the Rundown, you can see more video of Mr. Obama and other presidents reaching out to communities in times of trouble.