Diplomacy, of course, is as much about symbolism as substance, but the latest example belongs in the record books: international anxiety about Washington’s Iran policy has become oddly entangled in diplomatic protocol. Middle Eastern leaders allied with the U.S. are showing their displeasure with the course of the P5+1 talks with Iran by either arriving on these shores without a presidential invitation to make their objections known, or the opposite — implicitly making their objections known by turning down a presidential invitation.

It started over two months ago, when Israeli Prime Minister Benjamin Netanyahu accepted an offer from House Speaker John Boehner to address a joint session of Congress on March 3, without a presidential invitation. Piqued by this defiance of protocol, the president did not meet with him, and several dozen Democratic congressmen boycotted the session. In his speech, the prime minister extolled the U.S.-Israel relationship, but warned that the course of negotiations with Iran seemed likely to unwind the international sanctions regime that had brought Iran to the negotiating table, while leaving Tehran with the means of achieving nuclear weapons capability.

His audience — nearly 90 percent of Senate and House members — proved receptive to the message. They drafted a bill requiring some degree of congressional review of any agreement with Iran. Seeing that its supporters had the votes to pass the bill over a veto, President Obama said he would sign it. Meanwhile, on April 2, the P5+1 reached a framework agreement with Iran and negotiations continued on a final deal, with June 30 set as the deadline for completion. The Senate passed the review legislation on May 7 by 98-1 (the dissenter, Sen. Tom Cotton (R-AR), did not think it was strong enough), and the House followed suit by 400-25 a week later.

Surprise of surprises, it turns out that America’s Sunni allies in the region are just as worried as the Israelis. The pending deal, they believe, could leave them at the mercy of a nuclear-armed Iran at a time when Shi’ite forces backed by Iran are destabilizing countries throughout the Middle East. Saudi Arabia said it might respond by acquiring its own nuclear bomb, and other states are rumored to be contemplating a similar course. Hoping to calm their fears, the U.S. Administration announced a summit of the Gulf Cooperation Council — consisting of the U.S. and six oil-rich Gulf states — for May 13-14 at Camp David. To lend even greater diplomatic significance to the event, King Salman, the new monarch of Saudi Arabia — the most important of these countries, whose deep and close relationship with the U.S. spans decades — was promised a one-on-one meeting with President Obama in Washington before the summit.

In the end, though, not only did Saudi King Salman bow out, but so did the rulers of the United Arab Emirates, Bahrain, and Oman, all sending lower-ranking officials instead. Salman, the Saudis said, was needed at home to preside over a five-day ceasefire in Yemen, the king of Bahrain had to attend the Royal Windsor Horse Show in England, and the other two leaders cited health concerns. That left the emirs of Qatar and Kuwait as the only Gulf rulers to attend.

Arab diplomats have been more subtle than the Israeli prime minister, and none has openly criticized the Administration’s course as Netanyahu did in his speech to Congress. In fact Adel al-Jubeir, the newly-appointed Saudi foreign minister, expressed surprise when a reporter asked him if King Salman’s absence was meant as a snub, calling the suggestion “really off-base.”

But in the unanimous opinion of Middle East experts, a snub is what it was. Like the Israelis, the Sunni Arabs perceive the Americans as tilting toward Iran in the delicate Middle East balance of power, about to clear a path for it to become a threshold nuclear weapons state and, by removing sanctions, providing it with funds to continue financing terrorist activity regionally and globally.

By downgrading their level of participation at the Camp David summit, the Gulf states signaled their insistence on a far tougher line in the negotiations with Iran. It is not too late to consider the advice of our allies in the region and insist on a deal that keeps nuclear weapons out of Iranian hands.