Last weekend, 16 months after the Iran nuclear deal was signed in Vienna, the agreement sparked another angry exchange between Jerusalem and Washington.

While the flare-up ostensibly concerned US-Israel relations, it was more about internal Israeli politics.

The exchange began on Thursday with a speech by President Barack Obama at the Pentagon.

Referring to the Iran deal, he said: "By all accounts, it has worked exactly as we said it was going to work. The Israeli military and security community acknowledges that this has been a game-changer."

Without mentioning his name, this was a direct jab at Prime Minister Benjamin Netanyahu, who had called it "a very bad deal". Behind the scenes, Israel's defence and intelligence chiefs had been much more equivocal, and had said "there are good things in the deal".

However, the response from the Israeli side did not come from the Prime Minister's Office, but from the Defence Ministry, which put out a statement last Friday saying: "The Israeli defence establishment believes that agreements have value only if they are based on reality".

It added: "The Munich agreements didn't prevent World War Two and the Holocaust because their fundamental assumption - that Nazi Germany can be partner to any agreement - was false."

This comparison caused indignation in Washington, and Mr Netanyahu was quick to assure the US envoy, Dan Shapiro, that "Israel has no ally more important than the US". Sources in Mr Netanyahu's office briefed the media that the statement from the Defence Ministry was "childish".

Mr Netanyahu was, of course, the leading critic of the Iran deal in the first few months after it was signed, but since it became clear that Mr Obama had the votes in the Senate to block Republican opposition, the Israeli Prime Minister has largely kept silent.

In recent months, Mr Netanyahu has tried to improve relations with the Obama administration in the hope of signing a new, 10-year defence aid deal with the US. His aides now predict that the deal is close and the statement from the Defence Ministry was an indication of Mr Lieberman's anger at being left out of the talks. It was also an attempt to stake out a position on a right-wing political spectrum currently being monopolised by Education Minister Naftali Bennett.

Both Mr Netanyahu and Mr Lieberman are anxious not to lose their positions as leaders of the right to Mr Bennett. The question is: which right-winger can risk Washington's ire while playing to the choir at home?

The fact that the Defence Ministry retracted its Munich comparison on Monday was an indication of the delicate balance that the Israeli leaders are trying to strike.