For the ninth time, Michael Kirk faced an imposing task: Create simultaneous profiles of both presidential candidates. Interview everyone (except the candidates); ask everything, and hope there are differences between them.

The result – The Choice 2020: Trump vs. Biden on Frontline – is a compelling film that debuted Sept. 22, on PBS (check local listings), and is now available on YouTube, on the PBS Frontline page, and the PBS video app. (The show is also scheduled to rerun in October and November.)

Compared to Kirk's eight previous Choice films, it was more challenging than usual, with the interviews – usually two-hours-plus – done long-distance. "I shoot it remotely, with high-quality cameras," he told the Televisions Critics Association – in a remote press conference with a high-quality camera. Interviewees "know we are in it for the long haul."

But also easier. These two candidates have considerable contrasts. "Their lives have been sort of weirdly contradictory," Kirk said.

That's partly in obvious ways.

Donald Trump grew up rich. Joe Biden had a tough time – a stuttering problem, a modest-income childhood, the deaths of his wife and daughter, and later his son.

But the more significant difference was in a concept: What happens when you make a mistake?

Biden has made big ones, the film says. He used large portions of a British politician's speech as if he had written it; there were other accusations of plagiarism in speeches and even in college work; also, he misrepresented his college record.

"The Biden plagiarism story is so consistent" with him, Kirk said. Biden was a "terrible student, kind of lazy about a lot of stuff, very mediocre in terms of preparation."

But what followed was also typical. Biden apologized profusely, dropped out of the 1988 presidential race, and threw himself into the successful effort to reject Robert Bork for the Supreme Court.

For Donald Trump, there are no apologies. That reflects his father's "insistence that his son has to be a winner," Kirk said. It's a view that "winners are the only ones that are worth proclaiming."

So Trump convinced himself he was doing that, Kirk said. In his "own self-image, (he) had been a winner most of (his) life – forget the seven bankruptcies; forget the three wives."

And he forgot other missteps. One came in 1989, when a young banking executive was beaten and raped when she jogged in Central Park; five Black youths were arrested.

Racial tensions were high, Kirk said, when Trump "decides…to take out a full-page ad in four New York newspapers that cost him $86,000. And the ad is very incendiary, calling for the death penalty."

The men were convicted and – decades later – exonerated. There has been no apology.

The Choice also digs into Biden, Kirk said, telling "what drives him, the flaws, the big mistakes, the tremendous angst."

When Anita Hill accused Supreme Court nominee Clarence Thomas of sexual harassment and testified in Senate hearings (with four other women waiting to testify, as well), women criticized the work of Biden's all-male committee. Biden soon convinced two women to join his committee.

The Biden portrait shows someone who savors company. "People liked to be around him," a boyhood friend says. Peggy Noonan, a Republican speechwriter, describes his political style: "He likes the dance of it. He loves meeting people; he loved hugging people."

The Trump portrait shows someone following his dad's advice. Roger Stone, a friend, repeats the view of Roy Cohn, a lawyer to Joe McCarthy and mentor to Trump: "Never apologize; always attack." Stone adds: "One of the things he learned from Roy was the manipulation of the celebrity press."

Kirk did more than 50 interviews then boiled it all down. "He has a very deeply annotated script," said Frontline producer Raney Aronson-Rath.

The results can surprise, Kirk said. "You'll feel you know them anew…. It is the power of long-form journalism." And one that, every four years, returns to the short-form TV world.