During the “Missile Gap” of the 1950s and 1960s, the United States drastically overestimated the number of Soviet missiles, according to 189 documents recently released by the CIA and discussed by former CIA agents and historians on Monday at the John F. Kennedy Library in Boston.

The declassified documents “showed the Soviets didn’t really have an advantage,” Chief of the CIA’s Historical Collections Division Bruce S. Barkan said. During the Missile Gap period, there was a growing perception in the U.S. that the Soviet Union had hundreds of intercontinental ballistic missiles (ICBMs).

But a declassified document from Sept. 21, 1961—part of a larger set of newly released material called the Missile Gap Report—debunked this theory, providing evidence that the Soviets only had four ICBMs.

Former CIA agent John J. Bird coauthored the report and describes it as “the end of the Missile Gap.”

The study of the Missile Gap period is especially relevant because it relates to today’s situation in Iraq, North Korea, and Iran, said historian and author Fred Kaplan and Timothy Naftali, director of the Richard Nixon Presidential Library and Museum and a former Harvard student.

During the forum, there were several speakers ranging from historians to former CIA agents.

The panels and talks continued for about five hours. During the closing forum, the four speakers discussed the history and the importance of the Missile Gap.

Media Spokesperson for the CIA Office of Public Affairs Preston B. Golson ’02 said he thought that the forum was fascinating and representative.

“These sort of CIA classifications are all about key national security questions that affected history,” Golson said.

In 1956, the U.S. mistakenly believed that there was a bomber gap where the Soviets had gained an advantage in deploying bomber aircraft, largely due to a 1955 air show where the Soviets flew bombers in a loop. After the CIA discredited this, the bomber gap concept transformed in 1957 into the concept of a missile gap.

“Psychologically, we had fallen behind,” Kaplan said. He added that the U.S. also thought that 1961 would be a year of maximum danger when the Soviets would launch a surprise attack.

Simultaneously, Soviet spies in the U.S. were feeding information to the USSR about U.S. missile fears.

But President Eisenhower called for aerial reconnaissance and imaging satellites such as the Corona Satellite, tools which eventually helped the U.S. realize that the Soviets were bluffing.

The CIA’s Historical Collections Division is responsible for declassifying historical documents—often holding forums afterwards to explain the documents’ significance to the public.

“We declassify as much as possible when we can,” Barkan said. “It adds to the body of knowledge and researchers get new information.”

But national security prevents some documents from being declassified, Barkan said.

The “number one concern is we still want to protect national security,” Barkan said. “Subject matter experts go through info using guidelines and see what can be released.”