We've asked John Dickerson for a look ahead.

Presidential campaigns are sometimes compared to a job interview.

Voters or the hiring committee debates the in-person office visit, but we already know Joe Biden and Donald Trump.

To learn whether they will protect the Constitution, how they manage a crisis, or whether they have the character and temperament, we can look to their records in the office of the job that they want.

So what is the point of this debate? First, debates showcase the job seekers' performance skills, presidential bearing, warmth, and command.

Even though we've seen these two perform a lot, it's a chance for candidates to reverse the stylistic misimpressions among voters who haven't paid much attention.

Plus, the context changes in a presidency.

Ronald Reagan was a well-known incumbent in 1984, but at 73 years old, he was asked about his age, a concern voters tell pollsters they have about the 81-year-old Joe Biden. "I will not make age an issue of this campaign.

I am not going to exploit, for political purposes, my opponent's youth and inexperience." The canned one-liner showed Reagan could navigate the shifting public sentiment he faced in office.

On substance, this debate can illuminate not just what these candidates believe, but what's at the core of those beliefs.

Circumstances will change when they're in office.

What hard wiring will guide them?

What values will guide them as they use the power that they've been given?

Will any? Every candidate's nightmare?

The gaffe that becomes the story.

Like Ford's claim in 1976. "There is no Soviet domination of Eastern Europe, and there never will be under a Ford administration." The Soviets did dominate Eastern Europe. "I don't believe that the polls..." Ford seemed out of it and repeated himself, insisting on something that was not so. They rigged the presidential election of 2020.

Donald Trump also insists on something that is not so, that he won the 2020 election, which he lost.

Not a gaffe, but a lie.

Top Republicans in the House and Senate said that lie led to a violent attempt to block the will of the people.

Trump still tells this lie.

Can you have a debate built on reason to measure reason when a candidate insists on something beyond reason?

The analogy collapses.

Not an interview anymore, but a hostile takeover, where the majority of the hiring committee is pushed out of the room.