The prime minister of Israel, Benjamin Netanyahu, responded to the Iran deal as expected: It is bad, endangers Israel, he argued; we are against it and will be the only American ally not only to oppose it, but to go down gloriously, fighting a battle in Congress that we are destined to lose.

Mr. Netanyahu often warns that Iran is like Nazi Germany in 1938, fooling naïve appeasers even as it plans a cataclysm for Jews. But only those who never see merit in any proposal and never initiate their own could respond as the Israeli leader has.

Not that the agreement is without faults. President Obama negotiated from a position of weakness and conveyed a message that failure to obtain a deal was not an option. He misguidedly took the military option off the table long ago and made it clear that a return to sanctions would be a poor outcome.

Indeed, Iran will be allowed to retain its nuclear infrastructure instead of dismantling it, and most parts of the agreement are limited to 10 to 15 years, instead of being permanent. It remains to be seen what inspections Iran will actually allow, and the dispute resolution mechanism is cumbersome.