Twenty environmental and civil liberties groups are fighting back against lawsuits they believe are aimed at limiting free speech and silencing critics.

The "Protect the Protest" task force announced Tuesday targets what are known as strategic lawsuits against public participation, or SLAPP, which use legal action and the threat of financial risk to deter people and groups from speaking out against something they oppose.

"We know from our own experience that this legal bullying tactic will work if it's not shut down," said Katie Redford, co-founder and director of EarthRights International.

The effort is to include billboard advertisements, training sessions for journalists and nonprofits, panel discussions and rallies outside the corporate offices of companies the groups believe use such lawsuits.

Rallies are planned next week in San Francisco, New York City and Dallas. Dallas is the base for Energy Transfer Partners, the company that built the Dakota Access oil pipeline and sued Greenpeace, Earth First and BankTrack for up to $1 billion for allegedly working to undermine the $3.8 billion project to move North Dakota oil to a shipping point in Illinois.

Greenpeace and the Center for Constitutional Rights, which also is involved in helping defend against that lawsuit, are among the Protect the Protest participants.

Spokeswomen for ETP did not immediately respond to a request for comment Tuesday.

The company's lawsuit filed a year ago alleges the environmental groups disseminated false and misleading information about the project and interfered with its construction. ETP maintains that the groups' actions interfered with its business, facilitated crimes and acts of terrorism, incited violence, targeted financial institutions that backed the project, and violated defamation and racketeering laws. The groups maintained the lawsuit was an attack on free speech.

U.S. District Judge Billy Roy Wilson this summer dismissed both BankTrack and Earth First as defendants. He said ETP failed to make a case that Earth First is an entity that can be sued, and that BankTrack's actions in imploring banks not to fund the pipeline did not amount to radical ecoterrorism.

EarthRights International helped defend BankTrack, assistance that Redford said exemplifies the type of collective effort the task force will bring.

Wilson also ordered ETP to clarify its claims against Greenpeace, and has given that group until Sept. 4 to file its response to ETP's amended complaint.

Greenpeace USA Executive Director Annie Leonard on Tuesday said a $300 million lawsuit filed against the group by the Canadian timber industry over its forest protection advocacy is another example of the type of lawsuits the task force hopes to battle.

"A healthy democracy is a precondition for a healthy environment, and we can't have a healthy democracy without informed, engaged public dissent," she said.

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