King was on Secret Service Terrorist Threat List

For all his sabre-rattling about terrorists, King was once a suspect himself...
From the NYSun
"In 1984, the Secret Service listed him as a threat when President Reagan made a trip to Nassau County to watch a Special Olympics event."

"He forged links with leaders of the IRA and Sinn Fein in Ireland, and in America he hooked up with Irish Northern Aid, known as Noraid, a New York based group that the American, British, and Irish governments often accused of funneling guns and money to the IRA. At a time when the IRA's murder of Lord Mountbatten and its fierce bombing campaign in Britain and Ireland persuaded most American politicians to shun IRA-support groups, Mr. King displayed no such inhibitions. He spoke regularly at Noraid protests and became close to the group's publicity director, the Bronx lawyer Martin Galvin, a figure reviled by the British.
Mr. King's support for the IRA was unequivocal. In 1982, for instance, he told a pro-IRA rally in Nassau County: "We must pledge ourselves to support those brave men and women who this very moment are carrying forth the struggle against British imperialism in the streets of Belfast and Derry."
By the mid-1980s, the authorities on both sides of the Atlantic were openly hostile to Mr. King. On one occasion, a judge threw him out of a Belfast courtroom during the murder trial of IRA men because, in the judge's view, "he was an obvious collaborator with the IRA." When he attended other trials, the police singled him out for thorough body searches."