The Israel Project commissioned Olive Tree Strategies to run the poll. The results were derived from a national online survey. interviews of 1,978 registered voters, conducted July 21-24, 2015. The data were weighted to approximate a national sample of registered voters as defined by Pew Research. The survey has a margin of error of ±2.2% at a 95% level of confidence.
The President's overall approval ratings had increased in the spring of 2015, but sank once the P5+1 deal was announced. Gallup has similar results.
Obama's biggest drop from his overall approval is in his foreign policy and his numbers on the Iran deal. While the numbers are still positive, it does show the controversy about the deal is eroding his support amongst Democratic Party voters.
Also significant is voters disliked the deal the more they knew about it. In the chart below the respondents were asked about the deal three times. The first time (top numbers) they were asked the generic statement from the slide above.
The second set of responses after consumers were given a set of positives about the deal (taken directly from Whitehouse.gov) and the same number of negatives.
The positives and negatives were rotated in order to ensure neutrality. With slightly more information voters disliked the deal even more.
The third set of numbers were taken after voters were given a list of concerns some have made about the deal. The numbers fell even further amongst each of the voting groups.
The below is the entire questionnaire with the results which along with the information above presents voter's opinions about specific issues surrounding the deal. What seems to be happening is as the debate continues and voters learn more about the deal support of the P5+1 agreement is dropping. As it should be as additional revelations about the deal beyond the White House spin is informing the voting public.