The key casting choices have been made for PBS, and the stars are John McCain and Barack Obama.

The 2008 presidential election will be the marquee primetime offering on the pubcaster this fall, with PBS orienting several news and documentary programs around the campaign.

After filling its primetime hours last week with the Republican National Convention, PBS will follow with a series of “Frontline” episodes on candidates McCain and Obama and the issues they face, culminating in a post-election, fly-on-the-wall doc of the campaign Nov. 11. These will be complemented by encore airings of “American Experience” that focus on past presidents.

Overall, PBS will retain its usual eclecticism, including an unusual addition to its “American Masters” series — “You Must Remember This: The Warner Bros. Story,” a six-hour retrospective airing Sept. 23-25.

“It’s hard to say a studio is an ‘American Master,’ but if you look at the output of the studio, and you look at the brothers behind it, they did have a particular view and particular approach and impact on America,” says PBS senior veep and chief TV programmer John Wilson.

The different threads of celebrity and the ruling class will weave together over three Wednesdays in November with the airing of “Monarchy: The Royal Family at Work” (a BBC production that drew controversy in the U.K. last year over a misleadingly edited trailer).