When President Obama sits down for dinner Wednesday night with representatives of Persian Gulf countries, he really hopes no one mentions that these were not the guests he initially invited. Forget that the Saudi king is AWOL, and forget that the leaders of Bahrain, Oman, and the United Arab Emirates also are staying home. Also, forget that only Kuwait and Qatar are sending their emirs.

That's why the White House has mounted an aggressive campaign over the past two days to obscure the fact that the Camp David summit with the six members of the Gulf Cooperation Council is not meeting the expectations set 40 days ago when the president announced it in the Rose Garden.

At the time, Obama coupled the announcement with the statement that he had just gotten off the phone with Saudi King Salman, implying that the summit had his backing. And until Friday, U.S. officials were confident that the king would arrive in D.C. on Wednesday for a private one-on-one talk with Obama.

So while the White House was a little slow to respond when the Saudis stunned Washington by stating that the king was staying home and sending lower-level officials, it has recovered with a media blitz touting the official line that everything is going just the way the summit planners wanted.

"We very much feel that we have the right group of people around the table to have a very substantive discussion," Ben Rhodes, the president's deputy national security adviser for strategic communications, told reporters Monday. In case they missed that, he repeated, "We're very pleased and feel like we have the exact right people around the table." And again: "It's, we believe, the right degree of representation...." Then Tuesday, on MSNBC's Andrea Mitchell Reports, he hammered home the point twice more: "We feel the right people are going to be sitting down at Camp David...." And: "We have the right people who will be sitting down with us at Camp David."

It is as if the White House hadn't really wanted the Saudi king to visit and were preparing all along to celebrate his substitutes, Crown Prince Mohammed bin Nayef and Deputy Crown Prince Mohammed bin Salman. These, crowed Rhodes, "have been key figures in setting that security policy for the Kingdom of Saudi Arabia, and key interlocutors for us."

Press secretary Josh Earnest lamented that the "word of the day" Monday was "snub," a word the White House now is trying to erase from the media's vocabulary.

When Mitchell told Rhodes "this is a snub," he protested, "No, absolutely not." To back up his contention, he quoted the Saudi foreign minister as stating he is "very happy with the summit preparations," adding, "Neither the United States or Saudi Arabia sees this in any way as a snub."

If not a snub, it was, by most accounts, one of the most diplomatically embarrassing moments for any recent president. Analysts accustomed to presidents working out the details and arrangements before announcing summits have struggled to find any apt precedents.

"I can't think of anything falling apart like this in quite this dramatic a fashion," said David Ottaway, a senior scholar with the Middle East Program at the Wilson Center. "What's really striking is how suddenly this happened. They waited until the last minute to say he's not coming. That makes it look as if, indeed, it is a snub. And they are sending a signal of dissatisfaction with Obama."

That dissatisfaction is why the summit was originally called. And it presents the major challenge to the president as he tries to use these two days to reassure the six Gulf countries that the United States sees their security situation the same way they do. At the heart of all the discussions is the same threat that is believed to have driven a wedge between Saudi and U.S. diplomats—Iran.

The administration would dearly love to have the GCC leaders endorse the allied nuclear talks with Iran, in effect isolating Israel as the loudest voice in protest of the talks. But the Gulf leaders see Iran as the biggest threat to their security and fear Obama is too focused on the nuclear talks to fully appreciate Iran's troublemaking in Syria, in Iraq, and in Yemen. They don't want Iran to have nuclear capability, but they are more worried about other threats.

They particularly object to Secretary of State John Kerry telling them that other threats such as the Islamic State are as dangerous as Iran. "He is trying to diffuse their focus on Iran. And this is not appreciated right now when they are in a showdown with Iran in Yemen," said Ottaway, who just returned from 10 days of meetings with top officials in Saudi Arabia. "Yemen may have been the decisive factor in the king's decision not to come because I think we are really on different wavelengths over Yemen.... They're worried that the Americans are not going to stay with them in an open-ended military campaign in Yemen."

Jon Alterman, director of the Middle East Program at the Center for Strategic and International Studies, also sees the divide. "You have really fundamentally different U.S. assessments of what the problem is and what to do," he said.

It is why several of the GCC countries have been pushing for formal, written treaties in which the United States would pledge to come to their defense if they were attacked. The White House has balked at those requests, though, believing any such treaty would face very tough sledding in the Senate. Instead, they have offered the same kinds of informal pledges as offered by all recent U.S. administrations.

It is also why there is likely to be a heavy emphasis at the Camp David talks on further arms sales to the region and making progress on the long-standing American push for a regional missile-defense system.

Such measures would combine words and actions to give the Gulf leaders what even the White House acknowledges they want most—American reassurance. "There's just this sort of amorphous sense they want to make sure the U.S. is there (and) will be with them," said Rob Malley, the NSC coordinator for the Middle East, North Africa and the Gulf Region. "All these stories about the U.S. pivoting or sort of being fatigued with the problems in the Middle East."

He added, "They just want to hear that we're there and that we care. And I think ... that's what Camp David is actually going to do." The region's most powerful monarch just won't be there to hear the message.

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