The more people hear the details of the agreement with Iran, the more they want Congress to stop it. In the latest CNN poll, the majority desiring Congress to block the deal has grow by four points to 56%, while support has dropped from 44% to 41%. That change is incremental, just outside the margin of error, but the trend is clearly going the wrong way for the White House. Meanwhile, Obama’s job approval rating — after briefly poking its head above the waves — has dropped back underwater at 47/51. CNN calls this “a real negative shift” in perceptions of Obama:

The poll on Iran also shows some interesting inconsistencies. Prior to asking that question, CNN’s survey asks whether people would support a deal with Iran that alleviates sanctions in exchange for limitations and inspections on its nuclear program rather than having it dismantled. That gets a bare-majority support at 50/46, down from 53/43 in April but still slightly to the positive. The Obama administration argues that this is precisely what the agreement does, but clearly Americans aren’t buying it. With the AP’s scoop yesterday that inspections of facilities like Parchin will be conducted by the Iranians themselves — a revelation that emerged after this survey was taken — expect the distrust to mount even further.

If the poll shows a dichotomy on policy, it displays none at all about Barack Obama’s performance on Iran. His approval rating on this issue in April was split, 48/48. Four months later, it has plunged to 38/60, and suddenly foreign policy has become an albatross again for the White House. This has implications for the presidential race in 2016, although perhaps indirectly. With Hillary Clinton imploding, some have suggested that John Kerry might make a good alternative for Democrats, with one news outlet noting a month ago that Kerry was “riding high” on the diplomatic success he’d made in Geneva on this deal. Hillary herself came out in favor of the deal, albeit hedging her bets a bit. These numbers show that the deal may become a poison pill to Hillary and certainly to Kerry if he decides to make a run for the nomination.

The internals make the damage clear. Obama has majority disapproval on Iran policy among most of their key demos — women (43/54), college attendees (41/56), independents (36/61), and urban voters (41/54). Even in demos where they do well, there is a notable lack of enthusiasm. Non-white voters approve of Obama’s handling of Iran by only 52/45, and young voters by a whisker, 50/48. Even Democrats aren’t exactly united in support, with only a 66/30 approval rating.

The demos for the deal itself aren’t much better for the White House. Although the splits are narrower, the outcomes are identical. Obama and Kerry lose women, urban voters, and independents, the latter two groups by almost 20 points. Twenty-eight percent of Democrats oppose the deal; if that ratio carried over into Congress, Obama would see a veto of the rejection overridden. The longer this drags out — and especially after people find out about the IAEA’s agreement allowing Iran to self-inspect at its military facilities — the more difficulty Obama will have in trying to keep that ratio from reality on Capitol Hill.