I am on record predicting that a nuclear deal with Iran will founder on the opposition of the Islamic Republic’s Supreme Leader, Ali Khamenei. Iranian diplomats, I wrote in May, “will allow this round of negotiations to fail and bargain instead for an extension of the current interim agreement. It will get the extension and then play for time again. There will never be a final deal.”

I was vindicated on the first point in July, when John Kerry purchased a five-month extension for the talks with $2.8 billion in direct sanctions...