In July 1963, President Kennedy demanded of the newly-elected Israeli Prime Minister that he allow U.S. inspections of the Israeli nuclear facility at Dimona to make sure that the plant was “devoted exclusively to peaceful purposes.” U.S. support for Israel would be “seriously jeopardized” if the U.S. could not get information on doings at the facility, Kennedy said.

Kennedy stated his demands in a letter to Levi Eshkol dated July 5, 1963, less than ten days after Eshkol became prime minister of Israel. The document is in the Israel State Archive, and is online at the National Security Archive, in a section titled Israel and the Bomb.

Text below (thanks in part to the Jewish Virtual Library).

Avner Cohen, author of Israel and the Bomb, writes at the National Security Archive:

Not since President Eisenhower’s message to [David] Ben Gurion, in the midst of the Suez crisis in November 1956, had an American president been so blunt with an Israeli prime minister. Kennedy told Eshkol that the American commitment and support of Israel ‘could be seriously jeopardized’ if Israel did not let the United States obtain ‘reliable information’ about Israel’s efforts in the nuclear field. In the letter Kennedy presented specific demands on how the American inspection visits to Dimona should be executed. Since the United States had not been involved in the building of Dimona and no international law or agreement had been violated, Kennedy demands were indeed unprecedented. They amounted, in effect, to American ultimatum.

What’s the larger context?

In The Samson Option: Israel’s Nuclear Arsenal and American Foreign Policy (1991), Seymour Hersh reports that Kennedy was dead-set against Israel getting the bomb and frequently pressured David Ben-Gurion, Eshkol’s predecessor, to agree to inspections at Dimona. Kennedy even sold out his concerns about Palestinian refugees’ return in order to gain concessions on Dimona– much to the consternation of the State Department. Hersh says that the Israelis misled American inspectors at the site, which had gone “critical” in 1962 with the help of the French. And some members of Congress undercut Kennedy’s policy in private communications with the Israelis.

Lyndon Johnson succeeded Kennedy as president on November 22, 1963, of course. He was also opposed to Israel getting the bomb, Hersh says. “A nuclear Israel was unacceptable.” But Johnson was in the end more accommodating: “By the middle 1960s, the game was fixed: President Johnson and his advisers would pretend that the American inspections amounted to proof that Israel was not building the bomb, leaving unblemished America’s newly reaffirmed support for nuclear nonproliferation.”

“Unlike Kennedy, Johnson was not eager for a confrontation,” Michael Karpin writes in The Bomb in the Basement. “He preferred compromise.” Israel achieved nuclear capability in 1966, he says.

Both Karpin and Hersh attribute Johnson’s winking acceptance of Israel into the nuclear club to his sensitivity to the Jewish experience in the Holocaust and the effect of what both men call “the Jewish lobby.” Hersh mentions Johnson’s dependence on financial contributions from Abraham Feinberg.

Here is that Kennedy letter: