ARI SHAPIRO, HOST:

The White House's guests for tonight's State of the Union were chosen to inspire people and to underline parts of the president's agenda. There's a police officer who adopted a baby from a couple addicted to opioids, a blind double-amputee who reenlisted in the Marines after he was injured in Iraq and Ohio business owners who are expanding their manufacturing company. This tradition started with President Reagan. And to tell us more about the origins of the practice, Gerhard Peters of the American Presidency Project joins us now. Hi.

GERHARD PETERS: Hi. How are you?

SHAPIRO: I'm fine. I understand there's actually a term for these guests. What is it?

PETERS: Yes, indeed. They're called Skutniks, named after Lenny Skutnik. He was a federal government employee heading to work. And Air Florida had a plane that crashed into a bridge over the Potomac River. The river was icy, and he saved one person.

SHAPIRO: And this was in 1982, right?

PETERS: Back in 1982, just a couple weeks before the State of the Union.

SHAPIRO: Let's listen to a clip of President Reagan's State of the Union address.

(SOUNDBITE OF ARCHIVED RECORDING)

RONALD REAGAN: Lenny Skutnik, who, when he saw a woman lose her grip on the helicopter line, dived into the water and dragged her to safety.

(APPLAUSE)

SHAPIRO: What was the reaction at the time? I mean, this must've been really dramatic.

PETERS: Oh, absolutely. And you know, we have to remember Ronald Reagan was an actor of course and...

SHAPIRO: Right - man of Hollywood.

PETERS: ...A man of Hollywood and understood, you know, how to use props, we'll call it, and, you know, how to personify things. And the practice has caught on. In almost every State of the Union address ever since, presidents have invited people into the gallery and acknowledged them.

SHAPIRO: Are there any that stand out in your mind from the years past?

PETERS: I think Rosa Parks acknowledged by President Clinton.

(SOUNDBITE OF ARCHIVED RECORDING)

BILL CLINTON: In a very real sense, this journey began 43 years ago when a woman named Rosa Parks sat down on a bus in Alabama and wouldn't get up. She's sitting down with the first lady tonight, and she may get up or not as she chooses.

(APPLAUSE)

PETERS: Remember back in 1990, it was George Herbert Walker Bush who actually acknowledged the man who would defeat him.

SHAPIRO: Wait; why was Bill Clinton the guest of George H.W. Bush?

PETERS: (Laughter) Well, Bill Clinton was 1 of 4 governors - two Republicans and two Democrats - who were there and acknowledged by the president because of their role with the administration in setting new education goals.

(SOUNDBITE OF ARCHIVED RECORDING)

GEORGE H W BUSH: And if I might, I'd like to say I'm very pleased that Governor Gardner and Governor Clinton, Governor Branstad, Governor Campbell, all of whom were very key in these discussions, these deliberations, are with us here tonight.

SHAPIRO: I wonder if George H.W. Bush later wished he hadn't invited them.

PETERS: Perhaps.

SHAPIRO: You perhaps jokingly referred to these people earlier as props. Are they just kind of tools for political theater?

PETERS: Well, I don't mean it to sound cynical when I say that, but they are people brought in by the president to help personify heroism but oftentimes also to help with the president in setting his agenda. It could be in the middle of the health care debate on the Affordable Care Act or when the president was encouraging Congress to raise the minimum wage or whatnot.

And you know, to bring someone in or to invite someone in and, you know, discuss about how a minimum wage increase would affect their lives, for example, is a way to try to push the agenda forward and try to change public opinion in the country to put pressure on Congress.

SHAPIRO: Gerhard Peters is co-director of the American Presidency Project at the University of California. Thanks so much for joining us.

PETERS: You're welcome. Thank you.