Pakistan is another story. The Saudis have a natural if unacknowledged claim on the technology: They financed much of the work done by A.Q. Khan, a Pakistani nuclear scientist who ended up peddling his nuclear wares abroad. It is widely presumed that Pakistan would provide Saudi Arabia with the technology, if not a weapon itself.

The Arab leader interviewed on Monday said that countries in the Gulf Cooperation Council, all to be represented at the Camp David meeting, had discussed a collective program of their own — couched, as Iran’s is, as a peaceful effort to develop nuclear energy. The United Arab Emirates signed a deal with the United States several years ago to build nuclear power plants, but it is prohibited under that plan from enriching its own uranium.

Over the last decade, the Saudi government has financed nuclear research projects but there is no evidence that it has ever tried to build or buy facilities of the kind Iran has assembled to master the fuel cycle, the independent production of the makings of a weapon.

Still, the Saudis have given the subject of nuclear armament more than passing thought. In the 1980s they bought a type of Chinese missile, called a DF-3, that could be used effectively only to deliver a nuclear weapon because the missiles were too large and inaccurate for any other purpose. American officials, led by Robert M. Gates, then the director of the C.I.A., protested. There is no evidence the Saudis ever obtained warheads to fit atop the missiles.

Mr. Obama met with Saudi princes in the Oval Office on Wednesday — Crown Prince Mohammed bin Nayef and Deputy Crown Prince Mohammed bin Salman — who will most likely moderate their criticisms of his administration while talking directly to the president. Mr. Obama is expected to offer them and the other Arab states some security assurances, although not as explicit or legally binding as the kind that protect American treaty allies, from NATO to Japan to South Korea.

But Mr. Obama will have a difficult time overcoming the deep suspicions that the Saudis, and other Arab leaders, harbor about the Iran deal. Several of them have said that the critical problem with the tentative agreements, as described by the White House and Secretary of State John Kerry, is that they assure nothing on a permanent basis.