US lawmakers press State Department for clarity on Israel’s nuclear capabilities

A group of Democratic lawmakers in the US Congress is pushing the State Department to address a long-avoided question: what, exactly, is known about Israel’s nuclear arsenal.

In a letter sent to Marco Rubio, the lawmakers argue that the ongoing US-Israel war on Iran has made the issue harder to sidestep. They say the lack of official clarity undermines efforts to manage nuclear risks in the region.

“Congress has a constitutional responsibility to be fully informed about the nuclear balance in the Middle East, the risk of escalation by any party to this conflict, and the administration’s planning and contingencies for such scenarios,” the letter states. “We do not believe we have received that information.”

At the centre of the request is Washington’s long-standing policy of ambiguity. Israel has never officially confirmed possessing nuclear weapons, maintaining what analysts describe as “nuclear opacity”, even as it is widely believed to have had such capabilities since the 1960s. Successive US administrations have largely mirrored that stance, avoiding direct acknowledgment.

The lawmakers argue that this approach is increasingly difficult to sustain. “A policy of official ambiguity about the nuclear capabilities of one party to this conflict makes coherent nonproliferation policy in the Middle East impossible,” the letter says, “for Iran, for Saudi Arabia, and for every other state in the region making decisions based on their perceptions of the capabilities of their neighbours.”

The questions they pose are unusually direct. They ask for details on Israel’s nuclear capabilities, including its warheads and delivery systems, and focus specifically on the Negev Nuclear Research Center, long seen as the core of Israel’s programme.

“Does Israel currently possess enrichment capabilities, and at what level?” the letter asks, seeking information on both fissile material and plutonium production. It also presses for insight into Israeli policy: whether the government has articulated any “nuclear doctrine, red lines, or thresholds for nuclear use in the context of the current conflict with Iran”, and whether the US has received assurances that such weapons would not be used.

Publicly available information on Israel’s programme has accumulated over decades through intelligence assessments, whistleblower accounts and official statements. A 1968 CIA assessment concluded Israel had developed or was capable of developing nuclear weapons, while a reported understanding between US President Richard Nixon and Israeli Prime Minister Golda Meir allowed Israel to maintain ambiguity in exchange for reduced US pressure.

Later disclosures, including those by whistleblower Mordechai Vanunu in 1986, added detail to what had been an open secret. Estimates from the Nuclear Threat Initiative suggest Israel possesses around 90 nuclear warheads, along with delivery systems ranging from submarines to ballistic missiles.

Despite that body of evidence, coordinated pressure from Congress on the issue has been rare. Individual lawmakers have raised it in the past, but sustained scrutiny has been limited, reflecting decades of bipartisan support for Israel.

The current letter suggests a shift, even if a modest one. It comes as some lawmakers have begun to question elements of US policy toward Israel more openly, particularly in the context of the war in Gaza and tensions with Iran.