Alex GibneyAs the summer movie season begins Friday, what should you see? A new movie about a self-styled action hero, a larger-than-life character bankrolled by a fortune in corporate money, a man who wields enormous power, operates outside the law, fights for a cause, and runs up against his own overwhelming hubris? Or, you could go see 'Iron Man 2.'

Yes, Alex Gibney's documentary 'Casino Jack and the United States of Money,' the story of convicted lobbyist Jack Abramoff and the vast corruption scandal that centered around him, has a lot in common with the saga of cocky superhero Tony Stark, including a shared theatrical release date. Of course, 'Iron Man 2' is opening on more than 4,000 screens, while 'Casino Jack' is starting out on nine before expanding across the country over the course of the summer.

Still, that hasn't stopped the Oscar-winning Gibney from issuing a tongue-in-cheek challenge to 'Iron Man 2.' "We're going to go toe-to-toe with that motherf---er. We're going to take him out," Gibney told Moviefone during a recent interview. "Robert Downey, watch out. 'Casino Jack' is coming to get you." Alex GibneyAs the summer movie season begins Friday, what should you see? A new movie about a self-styled action hero, a larger-than-life character bankrolled by a fortune in corporate money, a man who wields enormous power, operates outside the law, fights for a cause, and runs up against his own overwhelming hubris? Or, you could go see 'Iron Man 2.'

Yes, Alex Gibney's documentary 'Casino Jack and the United States of Money,' the story of convicted lobbyist Jack Abramoff and the vast corruption scandal that centered around him, has a lot in common with the saga of cocky superhero Tony Stark, including a shared theatrical release date. Of course, 'Iron Man 2' is opening on more than 4,000 screens, while 'Casino Jack' is starting out on nine before expanding across the country over the course of the summer.

Still, that hasn't stopped the Oscar-winning Gibney from issuing a tongue-in-cheek challenge to 'Iron Man 2.' "We're going to go toe-to-toe with that motherf---er. We're going to take him out," Gibney told Moviefone during a recent interview. "Robert Downey, watch out. 'Casino Jack' is coming to get you."

Gibney, who won the Academy Award for Best Documentary two years ago for 'Taxi to the Dark Side,' a critical look at America's use of torture in the war on terror, is one of the busiest documentary filmmakers around. He spoke to us from his Manhattan office, where he was putting the finishing touches on several films, three of which were about to premiere at last week's Tribeca Film Festival. He managed to find time to talk to us about politics, making a difference with film, and how truth can be just as dramatically compelling as fiction.

"You can't make this s--t up," he said of Abramoff's remarkable story. "In it's own way, it's an action film. It tells you something about why we're in the mess that we're in, but it does so in a pretty entertaining way."

Jack AbramoffIf you watched HBO's 'Big Love' this season, you saw a subplot in which a lobbyist who specializes in representing Indian casinos secretly colludes with a religious right group to stage fake grassroots anti-gambling protests against one of her own client tribes because she's actually trying to stifle competition on behalf of a rival-casino-owning tribe that is also a client. As 'Casino Jack' reveals, that's exactly what Abramoff did, and it's one of the shadowy deals that ultimately got him into deep legal trouble in 2005. In 2006, he pleaded guilty to felony charges of conspiracy, wire fraud, mail fraud, and tax evasion, and was sentenced to four years in prison.

Before that, however, he was Washington's most powerful and well-connected lobbyist and a Republican true believer dedicated to deregulated capitalism. (This meant some shady clients, like Chinese sweatshop owners operating in the U.S. territory of the Northern Marianas Islands.) According to the film, he fancied himself something of a secret operative, a spy roaming the corridors of power. (In fact, one of his earliest lobbying efforts, on behalf of anti-communist insurgents in Angola, led to him writing and producing a Cold War action thriller, 1989's 'Red Scorpion.')

What's truly nauseating about the Abramoff story, however, is that much of what he did, funneling corporate cash to Congressmen to buy their votes, was perfectly legal. (And, as evidenced by Congress' current reluctance to pass financial reform laws curbing the kinds of Wall Street abuses that led to the 2008 economic collapse, continues to this day even in Abramoff's absence from the scene.) "All that stuff continues as if Jack was still in place," Gibney said. "It's not getting better. It's getting worse."

'Casino Jack and the United States of Money' trailer

Congress' dependence on lobbyist dollars is a problem for both Republicans and Democrats on Capitol Hill. "One of the most shocking things about this, whether you're a Democrat or a Republican, is the idea that our senators spend two to three days out of every week just dialing for dollars. When are they supposed to do our business?" Gibney said.

"Look, if you're a Republican who's angry about how much pork is dished out by Washington, D.C., you ought to be upset by this film because it shows just how powerful a role money plays. And the money is looking for handouts from the federal government. They're not just looking for deregulation. That's how it works," Gibney said. "The only way to stop that is to stop the amount of money that's flowing through the electoral system in terms of campaign financing. It's good for people on the left, it's good for people on the right."

Asked whether politically minded documentaries can really make a difference instead of just preaching to the choir, Gibney said, "Sometimes. I used to answer that completely in the negative. But I know that 'Taxi to the Dark Side,' because of the letters I've gotten, that it did change people's minds. That was very meaningful to me. And I think 'Casino Jack' has the opportunity to open people's eyes and maybe to change a few minds, too."

It'll be an interesting test to see which has more impact: Gibney's documentary or an upcoming fiction feature due this fall, simply titled 'Casino Jack,' starring Kevin Spacey as Abramoff. "Kevin Spacey is great," said Gibney, who's seen the rival film, "but he's no Jack Abramoff." He quoted something one of the lobbyist's associates says in his own movie to describe Abramoff's charisma and persuasiveness: "He could talk a dog off a meat truck."

Gibney's interviews with Abramoff don't appear in his documentary because the Justice Department wouldn't let the director film or even tape record them. Half-jokingly, Gibney said he hopes that when Abramoff is released later this year, he'll tour with the film. "He could denounce it. I hope he does," Gibney said. "I mean, I hope he likes it, but I'd be fine if he denounced it. He could talk with the film and tell people how it's done in Washington. That would be a real revelation."

• Follow Gary Susman on Twitter @garysusman.