So, what can Mr. Obama do in order to maximize diplomacy's chance of success despite structural congressional strictures? The answer is clear: Explore and exercise those foreign-policy options that cannot be easily hindered by Congress.
Ahead of these crucial negotiations, the president can do several things.
For one, he can pledge before the talks begin that if Iran makes concessions on its program, he will suspend executive sanctions (as opposed to congressional ones) and revoke asset seizures that were conducted through executive orders. The Treasury Department's Office of Financial Assets Control (OFAC) has tremendous latitude that Obama can use to ease pressure on Iran.
Making such a pledge would signal to Tehran that Washington is genuinely committed to making a deal, while setting a new tone for US allies in their approach to Iran. After all, if Obama takes this approach, they, too, would need to see that there will be a difference between the Iran policy of his first and second terms.
Second, while the president cannot control his own Congress, he can certainly work with the European Union and other allies, such as South Korea, Japan, Canada, and Australia, to make sure that they lift their own sets of sanctions against Iran if a reasonable agreement is reached.
It is true that parliamentary procedures and executive decisions in those countries are also clogged by political considerations and various lobbies when it comes to dealing with Iran. But pressure from the American government would prompt these US allies to transcend “domestic politics” and cooperate with Washington in its effort to settle the nuclear crisis.
In working with America’s allies, Obama would also signal that he's not only capable of uniting the Western world against Iran, as has been the administration's motto for the past four years, but that he's also able to unite them in conciliation with Iran when it's needed.