Could an Iran Deal Sway the Next Election?

(Bloomberg Opinion) -- International-relations scholar Dalia Dassa Kaye has a question after reading a New York Times story about the possibility of the U.S. rejoining and reviving the nuclear-weapons agreement with Iran:

This piece says the restoration of the JCPOA would “almost certainly become a campaign issue in the midterm elections.” What do American political analysts think? Will Americans base their votes on this issue?

The short answer is easy: No. Almost certainly not. Hardly anyone will change their vote regardless of what happens with the Iran deal.

The long answer is a little more complicated. As far as voting is concerned, there's very little evidence that anyone changes their mind based on foreign affairs. In fact, there's little evidence that international political events, even fairly dramatic ones, have much of an influence on presidential popularity, with the exception of short-lived rally effects. Even the most dramatic spike in the history of presidential polling, after the Sept. 11 attacks, gave George W. Bush a surge that took only about 15 months to dissipate. Normal rallies are gone in weeks, sometimes days.

The one big exception is that wars producing U.S. casualties do usually hurt a president's popularity, typically after an initial positive rally. The major examples are Harry Truman with Korea, Lyndon Johnson (and to some extent Richard Nixon) with Vietnam, and George W. Bush with Iraq. But winning a war doesn't really do much for a president. George H.W. Bush was president during a brief successful conflict with Panama, a decisive war with Iraq, and a very successful end to the Cold War. None of that saved him from a defeat when he sought re-election in 1992. (The most famous example of such a loss was from abroad: Winston Churchill lost soon after World War II. For that matter, Truman's Democrats lost majorities in both chambers of Congress in the first midterm after World War II.)

So my guess is that as long as war doesn't break out with Iran, President Joe Biden will be neither helped nor hurt by whatever happens.

That said, candidates do talk about foreign affairs during campaigns, whether or not voters pay attention. If the U.S. does re-enter the nuclear deal, Republicans will criticize Biden for that. If it doesn't, they'll blame him as Iran grows closer to testing a nuclear weapon. And campaign promises can be very important, whether they change election outcomes or not. Indeed, we've seen that twice now on this specific policy question: Donald Trump campaigned against the nuclear deal in 2016 and then withdrew from it, while Biden campaigned on re-entering and has worked toward doing so.

In part, these promises come about simply because candidates for federal office, especially governors and others who have only minimal foreign-policy experience, want to demonstrate competence in these areas. But another reason is because both Democrats and Republicans have groups within their parties that care a lot about foreign policy, in general or over specific policy areas. Winning support from those groups may be important for winning nominations. So candidates will try to align their policy preferences and priorities with them. And because foreign-policy experts within the Republican Party do tend to care a lot about Iran, we can expect Republican candidates to talk about it in 2022 and 2024. Regardless of what voters think.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Jonathan Bernstein is a Bloomberg Opinion columnist covering politics and policy. He taught political science at the University of Texas at San Antonio and DePauw University and wrote A Plain Blog About Politics.