By Scott Bransford

PORTLAND, Ore. (Reuters) - The six men and a woman charged with conspiracy in seizing a U.S. wildlife center in Oregon were staging a legitimate protest manipulated by the government through informants who infiltrated the group, a defense lawyer argued at their trial on Tuesday.

In protesting what they saw as a form of tyranny, the defendants themselves became victims of a government campaign to discredit and criminalize a larger movement opposed to federal control over millions of acres of public land in the West, Marcus Mumford argued.

Mumford, whose client, Ammon Bundy, led the armed takeover of the Malheur National Wildlife Refuge in eastern Oregon, summed up the defense case in federal court in Portland where Bundy and six others have stood trial since mid-September.

His closing argument followed the prosecution's summation and weeks of testimony by government and defense witnesses, some of whom took part in the 41-day occupation.

“You are the heart and lungs of liberty,” Mumford told jurors during an impassioned presentation lasting nearly four hours. “Only you can make clear that Mr. Bundy is not a conspirator and none of these men and women are conspirators.”

Earlier on Tuesday, Assistant U.S. Attorney Ethan Knight countered that Bundy and his followers had defied the rule of law, turning the wildlife refuge into an armed “fortress” from which to press their political beliefs.

The defendants are charged with conspiracy to impede federal officers through intimidation, threats or force, as well as with possession of firearms in a federal facility and theft of government property.

The immediate flashpoint for the takeover was sympathy for two Oregon ranchers who had just been ordered back to prison for setting fires that spread to federal land. But Bundy has said the occupation was motivated by a larger issue - abuse of private property rights through corrupt U.S. land-management policies.

“Is it illegal to tell the government to respect its limits?” Mumford asked the jurors. “Is it illegal to tell the government to respect the Constitution?”

Mumford said federal officials sought to manipulate the occupiers through the use of informants planted at the compound to help the government portray the protesters as “scary people.”

He cited evidence accepted by the court that nine government informants were present at the refuge during the occupation, furnishing intelligence to federal law enforcement while influencing the course of events there.

Jurors are expected to begin deliberations in the case as early as Thursday.

(Editing by Steve Gorman and Tom Brown)