What’s going on here is a high-stakes campaign to buy time — to slow Iran’s nuclear clock. Obama administration officials doubt that the Iranian regime is susceptible to a sudden change of heart on the desirability of nuclear weapons, but they do think that it can be induced to slow down, and that, in this game, any delay should count as a success. In the best-case scenario, the longer Iran’s nuclear work can be delayed, the greater the chance that a new government could assume power and decide on a change of course. The risk, of course, is that at some point Israel will decide that its survival requires a military strike.

The good news is that U.S. officials say there is still time for more diplomatic inroads. The Iranians aren’t able yet to produce large amounts of weapons-grade uranium.

The Obama administration deserves credit for getting as far as it has.