FORT SMITH, Ark. (AP) _ A reporter's videotape shows a white supremacist who is accused of sedition telling an audience, ''Hate is our law, revenge is our duty.''

Peter Lake of Los Angeles taped Richard G. Butler, 69, of Hayden Lake, Idaho, making the statement at two events in 1983: a cross burning in Los Angeles, and the swearing in of two Aryan Warriors, making them members of Butler's Aryan Nations group in Idaho.

Lake was the government's first witness in the trial of 14 white men in federal court - 10 on charges of plotting a violent overthrow of the government, five for plotting the murder of federal officials, and two for transporting stolen money.

He testified Thursday about how, using the name Peter Lawrence, he went to Butler's Aryan Nations compound in Hayden Lake and pretended to become a follower of the group's beliefs.

Butler, who knew he was being taped, made the statement in a context in which he said the Aryans had the law of hate and the duty of revenge so long as ''the alien is in the land'' and occupies ''the seat of power.''

Conviction of conspiring to overthrow the government by force has a maximum penalty of 20 years in prison and a $20,000 fine; plotting to murder federal officials has a maximum penalty of life imprisonment. Transporting stolen money has a maximum penalty of 10 years in prison and a $10,000 fine.

Lake, a writer and television producer, said he investigated Butler for a report for a Los Angeles TV station and a magazine published by Larry Flynt.

Under cross-examination, Lake said that he carried three .45-caliber pistols on an airliner in his luggage on the trip, that he lied to Butler and others at the compound, that he took the initiation as an Aryan Warrior insincerely, that no one ever told him that as a warrior he would have to kill or bomb or try to overthrow the government by violence, and that his companion on the trip, a felon, also was armed.

Because of the large number of defendants, opening statements took two days, even though four defendants put off statements until the government has finished its case.

Defendant Ardie McBrearty made his own statement, telling the jury that the government's case was ''a little truth here, a little truth there, and a whole lot of imagination in between.''

Attorney N.C. Deday LaRene said his client, the Rev. Robert Miles, of Cohoctah, Mich., believes the races should be separate. ''He speaks of being at war with the government,'' LaRene said, but likened Miles' rhetoric to a coach telling his players before a game, ''cripple them, go in there and kill them.''