It was only one paragraph buried deep in the most plain-vanilla kind of diplomatic document, 40 pages of dry language committing 189 nations to a world free of nuclear weapons. But it has become the latest source of friction between Israel and the US in a relationship that has lurched from crisis to crisis over the last few months.
At a meeting to review the Nuclear Nonproliferation Treaty in May, the US yielded to demands by Arab nations that the final document urge Israel to sign the treaty — a way of spotlighting its historically undeclared nuclear weapons.
Israel believed it had assurances from the Obama administration that it would reject efforts to include such a reference, an Israeli official said, and it saw this as another sign of unreliability by its most important ally. In a recent visit to Washington, Israel's defense minister, Ehud Barak, raised the issue in meetings with senior American officials.
With Prime Minister Benjamin Netanyahu scheduled to meet President Obama on Tuesday at the White House, the flap may introduce a discordant note into a meeting that both sides are eager to portray as a chance to turn the page after a rocky period.
Other things have changed notably for the better in American-Israeli relations since Netanyahu called off his last visit to the White House to rush home to deal with the crisis after Israel's deadly attack on a humanitarian aid flotilla sailing to Gaza in late May.
His agreement to ease the land blockade on Gaza, which came at the request of the US, has helped thaw the chill between the governments, US and Israeli officials said.
Meanwhile, the raft of new sanctions against Iran over its nuclear program, after the passage of the UN resolution, has reassured Israelis, who viewed Obama's attempts to engage Iran with unease. Obama signed the American sanctions into law on Thursday.
"The overall tone is more of a feel-good visit than we've seen in the past," said David Makovsky, director of the Project on the Middle East Peace Process at the Washington Institute for Near East Policy.
"It has been more focused on making sure that the Ides of March have passed."