Greenpeace is set to go on trial on Monday before a North Dakota jury in a bombshell lawsuit that, if successful, could bankrupt the storied group.

The Dallas-based company Energy Transfer sued Greenpeace in 2017, accusing it of masterminding raucous protests over the construction of the Dakota Access Pipeline near the Standing Rock Sioux Reservation nearly a decade ago. The activists say the lawsuit is a thinly veiled tactic to suppress free speech and set a chilling precedent for protest groups, and that Greenpeace played only a supporting role in demonstrations that were led by Native Americans.

“This trial is a critical test of the future of the First Amendment, both freedom of speech and peaceful protest under the Trump administration and beyond,” Greenpeace’s interim director, Sushma Raman, said in public remarks on Thursday.

Energy Transfer declined to comment in advance of the trial. In a statement in August, it said the lawsuit against Greenpeace was “not about free speech as they are trying to claim. It is about them not following the law.”

Greenpeace said the damages sought would amount to $300 million, a figure that is more than 10 times the group’s annual budget. Two associated entities are also named as defendants: the Greenpeace Fund, which is based in Washington and awards grants to other groups, and Greenpeace International, which is based in the Netherlands.

The trial is scheduled to last five weeks at the state court in Mandan, N.D. Many observers are skeptical that Greenpeace, one of the most well-known environmental activist groups in the world, will be able to win over a jury in conservative North Dakota.

President Trump’s choice for interior secretary, Doug Burgum, was the governor of the state until last year. Kelcy Warren, a founder and the executive chairman of Energy Transfer LP, is a supporter of the president and a major donor.

The Dakota Access Pipeline was approved in 2016, spurring protests from Native Americans, who said that it would encroach on sacred land and endanger the water supply. The 1,170-mile pipeline carries oil from North Dakota to Illinois.

Thousands of people traveled from around the country to join a monthslong encampment near the reservation, and tribal leaders sued to stop the pipeline. They used the slogan “Water Is Life.” The police and private security clashed with protesters on numerous occasions, and Energy Transfer said crucial equipment was damaged and that its financing prospects were harmed.

Waniya Locke, an activist who lives on Standing Rock, said the movement had developed organically and been led by women. “We stood on the river banks unarmed,” she said.

The camp was eventually razed, and the pipeline is operating, through final approvals are still pending.

Energy Transfer’s lawsuit was first filed against a broader array of defendants in federal court in 2017, alleging violations of the Racketeer Influenced and Corrupt Organizations Act, or RICO, a statute designed to defeat organized crime. It was dismissed by Judge Billy Roy Wilson of the United States District Court for North Dakota, who wrote that the allegations fell “far short of what is needed to establish a RICO enterprise.”

A similar complaint was then filed in state court. The latest version of the lawsuit accuses the defendants of trespass, defamation, conspiracy and tortious interference with business. It says that Greenpeace spread misinformation that incited the protests and severely damaged its ability to run its business.

Deepa Padmanabha, a lawyer for Greenpeace, said that the group had supported the protests and that it had been involved in training people in nonviolent direct action, but that it was not central to the efforts. She said the claims involving trespass, in particular, sought to impose a “collective protest liability,” in which any group could be held responsible for the actions of every person in attendance.

She offered the example of a nonviolent protester being held liable for the actions of “unknown people who, for example, set fire to construction equipment.” She added that “it’s pretty easy to see how, if successful, this kind of tactic could have a serious chilling effect on anyone who might consider participating in a protest.”

Greenpeace considers the action a SLAPP, or a Strategic Lawsuit Against Public Participation, a term that refers to lawsuits that are intended to silence critics or to cost them time and money defending a case. Some American states, though not North Dakota, have laws that make it easier to dismiss lawsuits shown to be SLAPP cases. In the European Union, a new directive also offers some protection from them to groups within its borders.

Citing the E.U. directive and other Dutch laws, Greenpeace International this month filed a countersuit against Energy Transfer in Amsterdam, seeking to recover costs incurred during the litigation. Kristin Casper, general counsel for Greenpeace International, said the first hearing in that lawsuit will be held in July.