U.S. President Donald Trump became the fourth U.S. president to uphold the decades-long pledge not to press Israel to give up its nuclear weapons after a delegation of senior Israeli officials met with the then-national security adviser Michael Flynn at the White House, according to a report published in The New Yorker on Monday. But Flynn resigned amid the Russia scandal later that day.

The Israeli delegation, including ambassador Ron Dermer, visited the White House in 2017 and met with Trump's administration to discuss, among other topics, signing the secret letter. According to the report, it is unclear whether Israel's nuclear weapons issue is a matter of transmitting information between the administrations.

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The report said that White House aides felt blindsided by the request; they were unaware of the existence of the letters. "This is our fuckin' house," one of the aides said after feeling as though Israeli officials were pushing them around.

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When U.S. President Barack Obama was extended the same request eight years earlier, the White House reaction was similar. Only a select group of senior officials in the previous three administrations knew of the letters. But Prime Minister Benjamin Netanyahu did not trust Obama. "With Obama, we were all crazy," an Israeli official told The New Yorker.

Over the past four decades all U.S. presidents and Israeli prime ministers have stood by an agreement concerning Israel's worst kept secret: its undeclared nuclear arsenal. According to the agreement, the U.S. will not press Israel to give up its nuclear weapons so long as it keeps facing existential threats in the Middle East.

In 1969, Prime Minister Golda Meir met with U.S. President Richard Nixon and they reached an unwritten agreement that Israel would not declare or test its nuclear weapons. The unwritten deal would be renewed by the following U.S. administrations, until Bill Clinton. Netanyahu would not settle for an unwritten deal and during the Clinton administration in 1998, the first secret letter was drafted.

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Israel's nuclear facility, located in the Negev desert in southern Israel, was built with French assistance at the end of the 1950s and first began operating at the end of 1963. Israel had concealed the Dimona nuclear reactor from the U.S. until the reactor was an established fact. Between 1957 and 1960, Israel's effort to hide the project had been crowned a success.