It matters what Americans think of the Iran deal. Congress has a chance to vote on whether to kill it. The next president will have a say in executing it. And this thing could be around for 25 years, during which time Congress will likely continue trying for some kind of role. Lawmakers and politicians, in determining how to approach the Iran deal, will almost certainly consider public opinion.
So what does that public opinion look like? So far, polling results on the Iran deal, on their face, are baffling. Here are a few of the key polls so far:
Pew: 38 percent of American who are aware of the deal approve of it; 48 percent disapprove.
YouGov: 43 percent support the deal; 30 percent oppose.
PPP: 54 percent support the deal; 38 percent oppose.
Washington Post/ABC: 56 percent support; 37 percent oppose. Interestingly, though, 52 percent said they disapproved of Obama's "handling of the situation with Iran." And 64 percent said they were "not so confident" or "not at all confident" that the agreement will succeed in preventing Iran from developing a nuclear bomb.
What do all of these apparently contradictory numbers mean? One way to read these differences is to try to explain them by polling methodology; maybe asking different questions yields different results.
But you can also read the results as reflecting a confused public that is uncertain or unclear about the Iran deal, and takes its cues from both poll phrasing and partisanship. That matters for the deal's chances in Congress.
Wording makes a big difference
The Pew poll, which found plurality opposition to the Iran deal, and the YouGov and Post/ABC polls, which found the opposite, asked the question in very different ways.
Pew, for example, asked respondents, "How much, if anything, have you heard about a recent agreement on Iran’s nuclear program between Iran, the United States and other nations?" Pew followed up by asking, "From what you know, do you approve or disapprove of this agreement?" In other words, Pew did not prime respondents with very much information. The result was low support.
YouGov, on the other hand, introduced its question with a little summary — but one without very much information: "Several world powers, including the United States, have reached an international agreement that will limit Iran's nuclear activity in return for the lifting of major economic sanctions against Iran. Do you support or oppose this agreement?"
That phrasing got results that leaned a bit in favor of the deal. Now look at the way the Post/ABC poll referenced the deal in their questions — with a bit more information on how the deal is designed to work, which makes it sound better:
As you may know, the US and other countries have announced a deal to lift economic sanctions against Iran in exchange for Iran agreeing not to produce nuclear weapons. International inspectors would monitor Iran's facilities, and if Iran is caught breaking the agreement economic sanctions would be imposed again. Do you support or oppose this agreement?
When respondents heard this description, they liked it (same with the PPP poll, which also had a relatively detailed question). Looking at these four polls, it appears that the more information the pollster provided, the more likely the respondents were to support the deal.
There are two ways to read that. One is that the pollsters gave a skewed summary of the deal that biased respondents in favor of it.
Another is that a lot of Americans aren't following the Iran debate very closely. Indeed, an LA Jewish Journal poll found that 48 percent of Americans "don't know enough" about the deal to have an opinion on it. When people don't know a lot, they're more easily swayed by wording.
Ideology and partisanship also play a role in views of the deal
There's more going on here than just a lack of information, though: Partisanship and ideology are the big drivers of public opinion toward the nuclear deal.
The Huffington Post's Ariel Edwards-Levy points out that every poll on the Iran agreement has found one constant: Democrats tend to support the deal, and Republicans tend to oppose it.
This suggests that people who don't know a lot about the nitty-gritty of the deal may be projecting their partisan and ideological predispositions onto it: If you like Obama or you're a liberal, you like the deal. If you don't like Obama or you're a conservative, you don't like the deal.
FiveThirtyEight's Harry Enten looked at several months of polling on the Iran deal and found a strong correlation between "demographic groups who like Obama" and "demographic groups who liked the Iran deal":
Black, Democratic, liberal and younger voters were generally for the deal, while white, Republican, conservative and older voters were more likely to be opposed. In fact, you can explain 82 percent of the variation in support for the Iran deal in 18 subgroups just by knowing what Obama’s job approval rating was in each group.
Jewish opinion illustrates the dynamic in really striking fashion. Opponents of the deal, particularly those in Israel, say that the deal is bad for Israeli interests — something that typically is important to American Jewish voters. Yet an LA Jewish Journal poll found that a strong plurality (49 versus 31 percent) of American Jews support the deal.
In the Jewish Journal poll, self-defined Jewish liberals favored the deal's approval in Congress by a 72-18 margin; conservatives opposed, 81 to 8. Liberal American Jews outnumber conservatives pretty heavily, and overall Jewish numbers reflect that.
"The true and deeper divide in American Jewry is not about the Iran deal per se," Steven M. Cohen, a professor at Hebrew Union College who helped coordinate the poll, writes. "This issue is merely the latest place to witness the ongoing and maybe growing divide between the liberal and conservative wings of American Jewry."
Cohen's remarks apply just as well to the rest of America: Liberals like the deal (and they like Obama), while conservatives don't. Ideology and partisanship, more than anything else, determine how the public thinks about the deal.
Why the public's opinion matters
The fact that public opinion on the Iran deal tends to split along ideological lines is, in narrow political terms, good news for the Obama administration's hopes of preventing Congress from killing the deal.
Republicans would need a large number of Democratic votes in both houses of Congress to get a veto-proof majority to kill the Iran deal. That's a tough sell to begin with: In our modern era of polarized politics, Congress members tend to vote more consistently along party lines. It might be possible for Republicans to overcome this if the deal were broadly unpopular, but if liberals like it that will make it harder for them to attract a lot of Democratic allies.
It's possible that the anti-deal campaign from lobbying groups like the American Israel Public Affairs Commission (AIPAC) might swing some Democrats. But AIPAC failed utterly when it tried to rally Democrats to blow up the interim Iran deal in late 2014. AIPAC works best when it's backing policies that have broad public support, such as defense aid to Israel; it's just not well-positioned to overcome wide partisan gaps on polarized issued like this one.
It is safe to say from the polling that the Iran nuclear deal is not being heralded all across the nation as a historic success. But neither is there anywhere near enough public opposition, so far, to help Republicans kill the deal.