There are two things to say about the electoral effect of the Iran deal.
Barck Obama isn’t going to be up for re-election. Still, his approval rating will matter for Democrats in both 2014 and 2016.
The first thing—and it’s correct, as far as it goes—is that the deal won’t have any electoral effect, whatever happens. Smart analysts know that voters just don’t care very much about foreign policy. And this one … well, it’s pretty distant from the concerns of most voters. Iran’s nuclear program has been in the news for a long time, but it’s not headline stuff for the most part. No matter how much of a fuss there is about it in the press this week, most voters won’t engage. The blunt truth is that this too will be gone from the headlines before very long, anyway.
Without most voters paying any attention to it, that leaves only the most politically attentive, and they’ll divide the way they always do: as long as the balance of the coverage isn’t radically lopsided, Democrats will be inclined to support the administration, and Republicans will be inclined to oppose it. It’s true that some Democrats in Congress are opposed to the deal, but for most rank-and-file Democrats, the president is the opinion leader who matters.
In short—no change in the president’s approval rating. No electoral effects in either 2014 or 2016.