Future generations may regard "I.O.U.S.A." as the most important film of 2008.

Not the best. Not the most entertaining.

Just the most important.

The latest documentary from Patrick Creadon ("Wordplay") is about America's impending financial meltdown. It's creepier than Heath Ledger in "The Dark Knight" and way more upsetting than (SPOILER!) Mr. Big blowing off Carrie at the altar.

The subject is the national debt (already I can see your eyelids growing heavy) and the likelihood that before long other countries -- to whom we are deep in hock -- will start using their financial might to dictate terms to the U.S.A.

We'll see a high-speed economic pileup to make the Great Depression look like a fender bender. "Nuclear terrorism is the only thing worse," says one U.S. senator.

In short, we have a duty to watch this film. And of course most of us won't -- we go to the movies to escape bad news, not wallow in it.

The heroes of Creadon's doc are former U.S. comptroller general David Walker and Robert Bixby of the Concord Coalition, who have dedicated themselves to traveling the country preaching the gospel of monetary responsibility, both personal and national.

Their Fiscal Wake-Up Tour takes them to Congress, to colleges, to radio and TV stations, to church basements -- anywhere they can get the word out.

Creadon works hard to keep things lively. There are man-on-the-street interviews that highlight our woeful ignorance about economics. There are lots of animated graphics. There's a funny "SNL" skit about a one-page self-help book whose only advice is "Don't spend money you don't have." And this film has more pie charts than Tippin's.

But in the end it's a civics lesson. Slick, but a civics lesson.

Bixby and Walker believe that if we act quickly to reverse our credit-based way of life, America might avert disaster.

"If this was gloom and doom we wouldn't be doing it," Bixby says.

But it won't be easy. If the war on terror ended tomorrow, along with the total elimination of waste and duplication in the federal government and the abandonment of the Bush tax cuts, the situation still would not improve significantly. We're in that deep.

"I.O.U.S.A." professes to be nonpartisan. The facts aren't Democratic or Republican, liberal or conservative, we're told.

Maybe not, but you can't help but notice that humongous debt was run up during the Reagan and two Bush administrations (weren't they supposed to be conservative?) while those tax-and-spend Clintonistas balanced the budget and even created a surplus.

Of course, that's ancient history. By the time the next president is sworn in, the U.S.A. will be more than $9.5 trillion in debt.

Ultimately "I.O.U.S.A." is a call for leaders brave enough to do the politically unpopular thing.

Good luck with that.

B

I.O.U.S.A.

Director: Patrick Creadon

Cast: David Walker, Robert Bixby, Ron Paul, Robert E. Rubin

Running time: 1 hr., 25 min.

Rating: PG for some thematic elements

Location: Now playing in select cities