In the real world that these muddle-headed hardliners apparently don’t inhabit, the multi-lateral sanctions that Obama so painstakingly built during his first term are crumbling. Russia is already selling a sophisticated missile defense system to Teheran and European corporations are itching to trade again with Iran. Congress could impose the harshest sanctions imaginable and Iran would easily circumvent them.

Of course this reduced leverage doesn’t mean that the U.S. should give in on the critical fine print of the deal. As in any negotiation, one or both parties may walk away from the talks (or threaten to) at the 11th hour. The big ones always require some brinksmanship at the end.

At Camp David in 1978, President Carter was sure the talks had failed only hours before the breakthrough. At Dayton in 1995, the late Richard Holbrooke, the lead negotiator, had to conspicuously place the luggage of the U.S. delegation at the curb, signaling that the Americans were leaving, before the warring parties in the former Yugoslavia came back for one final fruitful session.

Going back to his days in the Illinois State Senate, Obama has been a poker player, though he doesn’t always play his hand well with Congress. Now he has to hold and fold with great finesse. If the president is too anxious for a deal and doesn’t double-rivet the details on inspections and snap-back sanctions, a cheating Iran—bent on a nuclear bomb—will overshadow his domestic accomplishments and render him a naïf on foreign policy.