WASHINGTON (CNN) -- In 1950, 12 days after the start of the Korean War, FBI director J. Edgar Hoover had a plan "to apprehend and detain persons who are potentially dangerous to the internal security of the country" -- thousands of them, almost all American citizens.
Hoover submitted the plan to President Harry Truman's special consultant for military and foreign affairs, Adm. Sidney Souers -- who had been the first director of the nascent Central Intelligence Agency in 1946 -- and to Souers' successor as Truman's top security aide, James Lay.
According to the plan, the United States was to round up suspects, detain them at federal prisons or military facilities and eventually allow them a hearing that would not be bound by the rules of evidence.
While parts of Hoover's approach are reminiscent of the way the Bush administration has tried to battle terrorism following September 11, 2001, author Ronald Kessler said he sees a big difference between that plan and the detention of suspected terrorists now. Kessler has penned several books about the FBI, including "The Bureau."
"The court has allowed all the measures that the Bush administration has used to find terrorists to continue," he said. "Congress has allowed all the measures to continue as well. So it's quite a contrast with the days of J. Edgar Hoover."
In Hoover's day, there were three possible outcomes of the hearing: detention, parole or release.
The plan made no distinction between American citizens and "alien enemies," although it was written so that only the sections about those "alien enemies" could be put into effect "if for some reason the full plan is not put into operation."
Habeas corpus -- the centuries-old protection against illegal detention -- would be suspended.
The U.S. Constitution allows suspension of habeas corpus only in the case of rebellion or invasion. But this plan added two other triggers: "threatened invasion" or "attack upon U.S. troops in legally occupied territory."
According to Hoover's letter to Souers -- declassified in a new report on Cold War intelligence matters between 1950 and 1995 and released by the State Department -- the FBI had spent years compiling a list of 12,000 names, 97 percent American citizens.
"Hoover kept these index cards where he would keep records on what people said, anything critical about the government, if they were pacifist, or if they knew someone who might be a communist," said Kessler.
The plan covered all the bases, from the president's initial declaration of an emergency situation to Congressional support of the plan.
"The plan contains a prepared document which should be referred to the President immediately upon the existence of one of the emergency situations for the President's signature," Hoover wrote. "Briefly, this proclamation recites the existence of the emergency situation and that in order to immediately protect the country against treason, espionage and sabotage the Attorney General is instructed to apprehend all individuals potentially dangerous to the internal security."
The plan also included a resolution for Congress to pass and an executive order for the president to issue validating the proclamation.
A footnote in the report reveals that Souers sent Hoover "a non-committal reply" and that there is no evidence Truman or any other president approved the plan.
The U.S. Supreme Court has ruled that American citizens cannot be denied habeas corpus and is expected to rule on whether some 300 non-citizens held at the detention center at Guantanamo Bay, Cuba, should enjoy that right.
Contacted by CNN, an FBI spokesman said the bureau had no comment on Hoover's letter. E-mail to a friend
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