After a long period in which Israel had pressed a wide international coalition to isolate Iran both diplomatically and financially, its leaders will now have to get used to the sight of some of their closest allies visiting Tehran.
The first to do so last weekend was German Vice-Chancellor Sigmar Gabriel, who arrived at the head of a large delegation of business people eager to beat their Western competitors in cracking open the Iranian market.
Mr Gabriel is the deputy to Chancellor Angela Merkel, who has repeatedly said that Germany's commitment to Israel's security is in its DNA and whose government is financing more than a quarter of the cost of German submarines and missile-boats for Israel's navy.
Mr Gabriel did not forget Israel in Tehran, telling his interlocutors there that "questioning this state's (Israel's) right to existence is something that we Germans cannot accept," and "you cannot have a good economic relationship with Germany in the long term if we do not discuss such issues too".
In response, Supreme Leader Ayatollah Ali Khamenei rejected any idea that Iran would change its policy on Israel.
Another Western ally about to take off for Tehran is French Foreign Minister Laurent Fabius, widely recognised as the toughest of the negotiators during the P5+1 talks, who is already adapting himself to the new landscape and planning his own business delegation.
Britain is also talking of re-opening its embassy in Tehran, closed since it was attacked by a mob in 2011.
Washington is Israel's biggest strategic ally but, more problematically, the main mover behind the agreement with Iran. Aides of Prime Minister Benjamin Netanyahu last week said that he would "kill himself" trying to secure a veto-proof majority against the deal in the two houses of Congress, which will be voting on the removal of sanctions in mid-September. Since then, however, he has toned down the rhetoric, and it is unclear whether Mr Netanyahu will back up that fighting talk with action. Most observers agree he has little prospect of winning that battle.
The US administration, meanwhile, is not waiting. It is seeking reassure Israel while lobbying members of Congress, particularly Democrats, to rally around the deal.
Leading the efforts to mollify Israel was Defence Secretary Ashton Carter, who arrived for talks in Jerusalem on Monday. He said that "the friendship and alliance with Israel" remained a primary US interest in the region. Meanwhile, Mr Obama's chief representative on the Hill, Vice-President Joe Biden, has been talking to the leaders of US Jewish organisations in an attempt to quash opposition to the deal.
Another factor that could force Mr Netanyahu to lower the tone of his opposition is the political trouble at home.
He has yet to agree with Finance Minister Moshe Kahlon on the long-overdue budget, and is faced with the dilemma of either enlarging the deficit or giving in to the demands of his coalition partners. The government is struggling to build a majority in the Knesset to push through its plans for regulation of the gas monopoly. On top of that, on Monday the Attorney General authorised a probe into the financial management of the prime minister's official and private residences.
While the Iran debacle will not cause the prime minister any direct political harm in the short term, it has hurt his image and therefore his power to deal with rivals.
Yesh Atid Leader Yair Lapid called for his resignation over what he described "the worst foreign policy failure since the state's establishment".
Adding fuel to the fire, Labour leader Isaac Herzog said: "the Netanyahu government failed in preventing the nuclear deal… he must be re-placed. We have to send him packing."
