Transcript for State of the Union Address: Unscripted Moments and Mishaps
And finally tonight, the president's about to give his big state of the union address, and all day, we were reminded of the strategies behind every move in that room. The handshakes, the seating arrangements and the unscripted moments. Abc's john donvan looks at what's happening behind the picture we see. The president of the united states! Reporter: You want to think pomp and ceremony like this is set in stone. In the constitution or some place, but actually, there's always been a fair amount of king and improve going on. Like look here, last years speech, the guy shaking the president's hand. The year before that, the same guy. More than ten years before -- same guy. 24 years before? Same guy. New york's elliott engel, who always gets there hours ahead of time. This afternoon, he had a space marked out already, but he risked stepping outside to tell us why he has to do this now. People would think I was sick or something if I didn't show up. Reporter: Other kinds of tweaks and improve. Well, there that's point to the here roams in the high seats thing, year after year. But it only started in 1982, when a man named lenny skutnik improved a rescue in real life. And ronald reagan's speech writer tweaked the speech that put lenny in that chair. Audience improv? tweaked the supreme court on a decision about campaign financing. And justice alito retweaked "not true." That wasn't in the script. But then, neither is elliot engel, who is always there, a fixture, overlooked by the constitution, but definitely part of the ceremony. John donvan, abc news, washington.
This transcript has been automatically generated and may not be 100% accurate.