If P.T. Barnum were still around, even he would have to concede: politics is the greatest show on earth.

Political personalities have long been known as showmen; President Teddy Roosevelt is remembered as much for his theater as his policy. But in the media age, the dividing line between entertainment and politics is becoming increasingly blurred. We expect our candidates to be actors, asking for honesty while shunning them when they give it to us.

It makes sense then that many of today’s most respected political commentators (at least as far as this paper’s demographic is concerned) are ostensibly entertainers – folks like Jon Stewart, Bill Maher and Minnesota’s own Al Franken.

“Al Franken: God Spoke” follows a year in the comedian-turned-ideologue’s life, picking up in the middle of a 2003 lawsuit brought by Bill O’Reilly and Fox News against Franken for his book, “Lies, and the Lying Liars Who Tell Them.” O’Reilly’s blotchy face was featured on the cover and, needless to say, he was more than a little cheesed.

But the bulk of the cinéma vérité documentary focuses on Franken’s effort at launching the nation’s first national liberal radio talk show network, Air America, trailing the comedian up through the 2004 elections.

There is no narration, only archived television clips and filmed scenes of conversations involving the increasingly haggard Franken telling the story. The time is split pretty evenly between Franken’s interactions with family members and various showdowns with his right-wing foes.

But it’s not clear what exactly the film accomplishes. It’s not a straight bio of Franken; granted, we get a few poignant moments of him speaking nostalgically of his father, as well as some of the more well-known clips from his erstwhile “Saturday Night Live” days. But these provide only minimal insight into his true personality. It often appears that when Franken’s on camera, he can’t help but act.

Nor does the film function terribly well as a position statement. It’s easy to gather that Franken sees Republican political domination as the scourge of the nation, and a few of the scenes were he debates GOP blowhards like Sean Hannity and Michael Medved, calling them out on bald-faced lies, are entertaining.

Still, one wonders if Franken sees the irony when he repeatedly states something to the effect of “I’m not polarizing, my opponents are polarizing!”

So if this isn’t a biopic, and it’s not a policy statement, then what is it? Perhaps the film functions best as a narrow, but still somewhat revealing, look at the state of America’s entertainment-driven political landscape.

It’s hard to imagine anybody who’s not a fan of Franken before the film finding much enjoyment in it – Rush Limbaugh’s followers won’t think it’s too terribly funny, nor will they be converted.

Conversely, judging from the reactions of folks in the Uptown Theatre Wednesday night, members of the choir will be more than eager to be preached to, greeting every half-funny quip and quasi-insightful observation with riotous laughter and applause.

Basically, if you’re the type of person for whom merely the sight of Dubya Bush is enough to make you laugh, this film is for you. Just don’t expect anything that will challenge your beliefs (you probably weren’t looking for that anyway).

Of course, there may be another purpose to the film, from Franken’s standpoint if not the filmmakers’. Though he still claims to be undecided, Franken has expressed interest in running for the United States Senate out of Minnesota in 2008. That being the case, it’s hard to imagine a better way to humanize himself in the face of potential voters than to have his daily goings on pasted across the big screen, human yet larger than life.

Franken, a lifelong entertainer, would seem to be a natural fit for the role of politician. The film then seems merely to be a warm-up. If and when Franken does decide to run, then the real show will begin.