At least, that's their story. The United States is suspicious that the true intent of the Iranian nuclear program is to produce enriched uranium to make bombs. Gadgets, as Robert Oppenheimer called them.

The United States does not want Iran to have gadgets. It wants Iran to shut down its uranium enrichment program. What does a nation that is sitting on a lake of oil, as Iran is, need with nuclear power? That's what the United States is asking.

Good question.

But under the Nuclear Nonproliferation Treaty, Iran has a right to make its own nuclear fuel. It's up to the International Atomic Energy Agency to watch Iran's nuclear program and make sure that the enriched uranium is for power plants, not bombs. The Iranians say the IAEA is free to watch. Iran has even set up cameras for that purpose.

Not good enough, says the United States. Iran lied about its nuclear program for 18 years, hid it from the world, and that is evidence enough that the mullahs from Tehran are up to no good.

The United States wants Iran hauled before the U.N. Security Council for sanctions. But the 35-nation board of the IAEA stopped short of recommending that last week. Instead, it passed a resolution expressing "serious concern," asked Iran to stop enrichment and called for the IAEA director to report back Sept. 3.

President Bush, though disappointed that Iran isn't going before the Security Council, pronounced himself satisfied that the IAEA governing board had made a good first step. What else could he do? In fact, the United States has few options.

It could attack Iran's nuclear facilities, but that would further inflame the Islamic world and add to the crushing U.S. military burden in Iraq.

It could try to buy Iran off, which is what Britain, France and Germany have tried in their negotiations with Iran. But that is not likely to work. The nuclear program is a matter of national pride and no Iranian leader with any political sense would offer to give it up.

That leaves the U.N. sanctions. But before other nations at the U.N. will agree to bring Iran up on charges, they must be sure that it really is pursuing a military program. So far, the evidence for that is purely circumstantial.

So the United States should bide its time and build its case. That, really, is the only option.