Emergildo Criollo is a leader in the Cofaan community. A lawsuit against Chevron alleges that 18 billion gallons of toxic wastewater were dumped into the Amazon, affecting indigenous people. (David Gilbert / First Run Features)
"Crude" sounds like the standard "this is an outrage" environmental degradation documentary, the latest in a line that includes "An Inconvenient Truth" and films about the death of the ocean, the evaporation of water, the murder of dolphins, even the disintegration of dirt. "Crude" fits that bill, but it is something considerably more interesting as well.

The outrage in question is the subject of a class-action suit filed by 30,000 citizens of Ecuador against Chevron, the world's fifth-largest corporation, alleging that 18 billion gallons of toxic wastewater were dumped into the Amazon between 1972 and 1990, fatally poisoning the land and water and sickening inhabitants. The lawsuit, with a potential cost to Chevron of $27 billion, has been going on for so long, 16 years and counting, that the original American oil company in Ecuador, Texaco, was acquired by Chevron and no longer exists.

Director Joe Berlinger ("Brothers Keeper," "Metallica") has been working on "Crude" for three years, and though he feared he was coming too late to the story, a verdict is still not in sight. Having all that time to explore the situation has paid off for Berlinger, enabling him to gain the confidence of his subjects and show us situations that ordinarily would not be open to outsiders.

For what "Crude" does best is take us behind the scenes and show in often candid detail how campaigns are waged, tactics decided on and strategies prioritized. For both sides realize that lawsuits like this one are not won or lost in the courtroom alone but in the critical realm of perception and public opinion.

"Crude" begins with a typical back-and-forth. In 2008, news clips show Pablo Fajardo, the lead attorney for the plaintiffs, and his associate, Luis Yanza, receiving the prestigious Goldman Environmental Prize. Then comes Chevron's reaction, as a representative says that the men have in effect made up the story for which they're being honored. What's going on here?

Next we see the charismatic Fajardo back in Ecuador and visiting a tiny Amazon enclave where the residents discuss, often in an indigenous language, the progress of the lawsuit. Periodically throughout the film we visit places like this and see the pervasive health problems that have resulted from wretched stewardship of the country's oil resources.

We also spend a great deal of time with a Spanish-speaking environmental lawyer from New York named Steven Donziger, someone who specializes in class-action suits and is a key legal advisor to Fajardo. We see and hear Donziger in all kinds of privileged situations, even with Joseph Kohn, the Philadelphia attorney whose firm is bankrolling the case and hopes to profit financially if Chevron loses.

Donziger not only discusses legal strategy but works hard to get the kind of publicity that will galvanize public opinion. His courtship of the forceful Trudie Styler, the co-founder, along with her husband, Sting, of the Rainforest Foundation, is shown in detail and is a fascinating case study of real-world political action.

Chevron, not surprisingly, does not allow Berlinger into similar meetings, but through statements by their attorneys and representatives, we get a clear idea of the shrewd ways the oil giant is fighting back at every turn.

The company's strategy is twofold. First is the culture of denial. To see apparently sincere Chevron representatives flat out contradict everything the plaintiffs are claiming shows the power stonewalling has to, at the very least, create doubt in the public mind.

Because that strategy doesn't work as well in Ecuador, where the damage is visible and hard to talk away, Chevron is ready with a moving-target series of fallback positions: Nothing was done that wasn't permitted by law, the Ecuadorean government signed off on a cleanup, most of the damage was done by the state-owned Petroecuador. Chevron also likes to claim that the only reason the suit was filed in the first place is because greedy U.S. attorneys are after the company's money.

It's true that the plaintiffs wouldn't have a prayer without American money and celebrity involvement, but does that mean their claims are any less just? It's still a David and Goliath story. What's different is that David has gotten his hands on some really choice stones.