Even if Congress rejects the agreement, do you think the Europeans, the Chinese or the Russians will reinstate sanctions? The result: The United States is left isolated while the rest of the world does thriving business with Iran.

Should Congress then give up? No. Congress needs to act in order to rob this deal of, at least, its domestic legitimacy. Rejection will make little difference on the ground. But it will make it easier for a successor president to legitimately reconsider an executive agreement (Obama dare not call it a treaty — it would be instantly rejected by the Senate) that garnered such pathetically little backing in either house of Congress.

It’s a future hope, but amid dire circumstances. By then, Iran will be flush with cash, legitimized as a normal international actor in good standing, recognized (as Obama once said) as “a very successful regional power.” Stopping Iran from going nuclear at that point will be infinitely more difficult and risky.