[W]e will consider any agreement regarding your nuclear-weapons program that is not approved by Congress as nothing more than an executive agreement between President Obama and Ayatollah Khamenei. The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of the agreement at any time.
The thing about most foreign policy decision-making is that a lot of it is irrevocable. In some cases it’s literally impossible: the United States can’t un-invade Iraq, for example. In other cases, the cumulative effects of certain choices renders a particular policy essentially locked in. The United States can’t really renegotiate NAFTA or dramatically curtail its economic opening to China, for example. Instances in which a future president legally reverses course on a prior president’s commitments — like, say, the George W. Bush administration’s reversals on the Kyoto Protocol and the International Criminal Court — inevitably trigger severe diplomatic blowback.
Obama’s negotiators should intimate that whomever the president will be in 2017, they’re going to be far less likely to compromise on [Iran].The great thing about this is that the 2016 candidates will be making Obama’s case for him. The one thing the 2016 campaign will produce in ample quantities is hawkish rhetoric. All Obama’s team has to do is point to these statements to make the case to the other side of the negotiating table about the need to deal now.