He was an enormously popular British talk-show host in England and Australia, a bon vivant whose TV stuff was frothy and exuberant - but would he have the chops to do the first serious interview with a fallen president of the United States?

David Frost said yes, he would. Most other people said no. So he put his own money - lots of it - on the project, for which he had to pay Richard Nixon, a production crew, and researchers. Then he banked on a risky notion: that the material he'd elicit from the notoriously evasive 37th president would make it worth top advertising bucks on TV.

The Frost/Nixon interview aired in 1977, three years after Nixon resigned amid the Watergate scandal. It was, at bottom, all about the bottom line - one of many points Peter Morgan drives home in his muscular, engrossing production of

Frost/Nixon

, about the interchanges that drew the largest audience ever for TV interviews.

Frost/Nixon

itself draws audiences; it's a coda to a defining piece of history in the memory of many Americans. The play was successful first in London, then on Broadway two seasons back, with a Tony-winning portrayal of Nixon by Frank Langella. Today, Morgan's screenplay of his stage work opens in wide release here and around the country, with Langella in a celluloid reprise of the role. (For a review of the film, see Page 4 of this section.)

And through Sunday, the national tour of the stage play - a production as arresting as the Broadway version - is being performed at the DuPont Theatre in Wilmington, the closest it will get to Philadelphia in its current traveling schedule.

Stacy Keach is the tour's Nixon, convincing not because of the way he looks, but through his body language, the cadence of his speech, and, like Langella, his understanding of the character.

In contrast to Langella's, the Nixon that Keach creates is a little more outgoing, played with a tad faster heartbeat. (I have not previewed Langella's screen version.) The two different stage Nixons are, to be sure, separated only by degrees, but each is real enough - or what we can perceive as real enough - to make us believe.

The national tour's David Frost - Sir David, now - is another convincing portrayal, by Alan Cox. The supporting cast is solid as well - Roxanna Hope as Frost's gal-pal, Bob Ari and Brian Sgambati as his researchers, Antony Hagopian as his initially reluctant producer, and Ted Koch as Nixon's head of staff.

Frost/Nixon

is Morgan's first venture into writing for live theater, but he dramatized another piece of history with his screenplay for

The Queen

, the well-received 2006 film about Britain's royal reaction to the death of Princess Diana.

That movie had the same real feel as

Frost/Nixon

, with depictions of people, many still alive, who made marks in the history of the world and the personal history of those in the audience.

I think he's on to something.

Frost/Nixon

Through Sunday at the DuPont Theatre, 1007

N. Market St., Wilmington. Tickets: $55-$70. 1-800-338-0881 or

.

Contact staff writer Howard Shapiro at 215-854-5727 or hshapiro@phillynews.com. Read his recent work at http://go.philly.com/howardshapiro.