Noah Millman considers the domestic politics of a negotiated nuclear deal with Iran:

My question is: does it matter? Will the Romney campaign’s inevitable criticism have any impact on the prospect of diplomacy’s success? My instinct is to say: no, it will have no meaningful impact, but I’m not sure. If a deal requires sending nuclear fuel to Iran in exchange for an agreement to open-ended IAEA inspections and a commitment to end enrichment beyond 3.5%, it’s easy to see how that would be demagogued as “agreeing to let Iran go nuclear.” Could the Obama Administration still sign on? Or would they have to push for an end to all enrichment, full stop, and thereby scuttle a deal?

I’m inclined to agree with Noah that Romney’s likely criticism of a deal with Iran wouldn’t matter to the Obama administration. I am less certain that it wouldn’t have some influence on Tehran’s willingness to follow through on a deal with one administration when it can’t be sure that Obama will still be in office a year from now. Iranian hard-liners might find Romney’s election to be a boon for them*, so they have an incentive to try to sabotage any agreement that would benefit Obama politically at home. If Romney expressed his opposition to a deal, Obama probably wouldn’t react to that by demanding more from Iran. Iranians inside the regime already skeptical of dealing with the U.S. might seize on Romney’s opposition as proof that any commitments the U.S. makes won’t mean anything if Romney wins. Iran’s government may assume that a Romney administration would impose new demands that makes any deal they negotiate now more or less meaningless over the long term. They might or might not be right about that, but it makes sense that they would find it difficult to reach an agreement that the next administration might not honor. Of course, Romney might prevent this from happening by not making opportunistic criticisms of Obama’s conduct of foreign policy during the general election, but I wouldn’t count on that.

* Contrary to a common assumption, hard-liners in other countries tend to prefer it when our government is headed by nationalists opposed to diplomatic engagement. It validates their preferences, and it makes it easier for them to marginalize the proponents of engagement on their side.