The problem is that wrecking the Iranian economy is just the means of U.S. policy. The goal is to get Iran to accept permanent limits on its nuclear and conventional military capabilities, as well as to curb its disruptive behavior in the Middle East. So far economic hardship hasn’t changed Iranian behavior and it may never do so. Pakistani President Ali Bhutto once vowed that his fellow countrymen and women will “eat grass, even go hungry, but we will get one of our own” nuclear weapons. And Pakistan eventually did. The Iranian regime may well feel the same way.