As the United States negotiated a nuclear test ban treaty roughly 44 years ago, President John F. Kennedy worried that public criticism from military brass could derail a deal, according to a newly declassified recording released Monday.

Kennedy was told during a meeting in the Oval Office with his top military aides on July 9, 1963 that several members of the Joint Chiefs of Staff were privately criticizing the idea of the test ban and might state their opposition publicly before Congress.

In the recording released by the John F. Kennedy Presidential Library & Museum, he is heard worrying about the timing of public criticism, as his lead negotiator was headed to Moscow for a final round of talks with the United Kingdom and the Soviet Union.

Maura Porter, declassification archivist at the library and museum, said Kennedy was worried that criticism before the initial pact was signed could derail the treaty. He hoped the nations could sign an initial pact, then have a debate in Congress before ratification, Porter said.

"I don't care who comes up and testifies — it ought to be wide open," Kennedy can be heard saying on the recording.

"That's the time you gotta say it and we haven't presented our case — then I can say this is why I am for it and that's the way — then the Chiefs can speak about the military disadvantages and advantages," Kennedy said.

Kennedy also sounds a bit surprised on the recording when told that not all the Joint Chiefs of Staff support the test ban.

In a radio and television address on July 26, 1963, Kennedy said the treaty represented the first time in many years that "the path of peace may be open" in the nuclear arms race.

"No one can be certain what the future will bring. No one can say whether the time has come for an easing of the struggle," Kennedy said. "But history and our own conscience will judge us harsher if we do not now make every effort to test our hopes by action, and this is the place to begin."

At the time, the Cold War was raging, and the superpowers were developing more powerful nuclear weapons. But after radioactive deposits were found in wheat and milk in the United States in 1959, public sentiment against nuclear testing intensified.

On August 5, 1963, the three nations signed an agreement to ban nuclear testing in the atmosphere, in space and under water. During the next two months, the treaty was debated and then ratified. It went into effect in October of that year.

Porter said the recording gives historical perspective on a very important debate at the time.

"I think (Kennedy) felt strongly that the test ban was a good idea and was in the national interest, and it wouldn't be a good idea to snuff debate," Porter said. "It was the timing of the debate that he had questioned."

At the time, some of Kennedy's advisers were opposed to the treaty because of concerns it would jeopardize the U.S. nuclear lead and shift the global military balance.

The 197-minute recording also includes additional meetings on the treaty, as well as previously released discussions on civil rights and the railroad works dispute.