Obama has a major TV booking most nights this week.

On Monday, he did Keith Olbermann’s popular MSNBC program, “Countdown.” On Wednesday, he’ll chat with David Letterman. For the second straight week, Obama is also a recurring face on Bill O’Reilly’s program. “The Factor” host keeps parceling out clips of their Republican National Convention interview.

Some Democrats criticized the Fox gambit, since it boosts O’Reilly and may do nothing for Obama, given that the audience is primarily made up of Republican senior citizens. As “O Force One” flew over Michigan on Monday, I raised that idea with Robert Gibbs, Obama’s communications strategist. He emphasized that, regardless of the media outlet, the goal is simply to get Obama’s message out during this critical phase of the campaign.

Jen Psaki, a traveling spokesperson for the senator, added that the media outreach complimented Obama’s political orientation. “This campaign has never been about speaking to just one wing of the party. We have visited parts of the country where Democrats have never been, and we are competing in parts of the country where Democrats have never competed,” she said. “Speaking to an audience that isn’t necessarily our base is par for the course — and part of the reason why Republicans and independents are taking a close look at Barack Obama,” Psaki added.

This outreach makes sense. Maybe Obama can pick off a few stray Republicans.

At a minimum, he might get more street cred with independents beyond O’Reilly’s base, if they think he proved his mettle under pressure. The hidden cost, however, is empowering O’Reilly to frame the debate.

I was reminded of that problem today during Obama’s press conference. The first question pressed Obama on his favorable remarks about the surge, from one of his feisty exchanges with O’Reilly. The real challenge, apparently, is winning over O’Reilly’s viewers without sounding like their hero.

While most news channels focused on Sen. John McCain’s big night on Thursday, it was a battle of the B.O.s on Fox News.

Sen. Barack Obama, the Democratic presidential nominee, made a much-hyped appearance on “The O’Reilly Factor” to tangle with Bill O’Reilly. The talk-show host had been pushing so hard for an Obama visit, of course, his unrequited desire was a big topic at the secret meeting between Obama, NewsCorp head Rupert Murdoch and Fox News chief Roger Ailes.

Ever the showman, O’Reilly turned his new tape into a mini-series — only “Part 1″ aired Thursday (below) — and turned us commentators into previews for the remaining segments. But it was still good television.

Part 1 is about national security, with O’Reilly gingerly mugging as a salt-of-the-earth armchair general. He may pull down $9 million a year, but O’Reilly talks with the cadence and umbrage of any regular guy holding court at the bar — scrunching his face, interrupting, waving his hands and wondering whether Obama is tough enough to take on Iran.

He looked permanently perturbed with Obama’s answers. But he also offered his guest a few compliments. So Obama was correct to oppose the Iraq war as the “wrong battlefield,” O’Reilly observed, but wrong to oppose the surge. (Don’t even bother trying to square that.) Obama gave a good speech in Denver, O’Reilly conceded, but he still “bloviated” about Pakistan.

Obama was cool and cogent throughout, but O’Reilly’s audience presents demographic kryptonite to his political superpowers. Fox News viewers went for Bush by 9:1 last cycle, and prime-time shows — like The Factor — offer an even more conservative spin than daytime programming. Meanwhile, the average age of an O’Reilly viewer is 71. Obama has trouble with older Americans in general, but older Americans who voted for President George W. Bush and tune into O’Reilly? Even they may not be moved by this solid performance: