Some people will be chagrined by this finding, others will be cheered. Different people will use it in ways that advance their own views. But I think there is a very, very strong case that most or all of change is a direct result of Prime Minister Benjamin Netanyahu's increasingly overt interventions as a partisan in American domestic politics.
Let's look at the chart.
As you can see, the change is quite recent rather than a slow build up over time. There are various ups and downs. But things are broadly stable from 2001 until about 2013. One thing I believe we can draw from this is that the occupation and the perennial stalemate in the peace process is not the triggering force of the change. It may be the underlying, root cause. But the occupation and all the rest surrounding it did not become much worse or more visible in the last three of four years. If anything since 2014 we've been in a relatively calm period. It's nothing like the wave of terrorism of the Second Intifada or the IDF incursions into the West Bank that followed.
So why the dramatic change? What happened during this period?
One big thing is Prime Minister Netanyahu's speech before Congress, focused in opposition to President Obama and arranged behind his back. That was in March 2015 - a completed unprecedented event. That was the most high profile event in Netanyahu's increasingly open alliance with the Republican party. But it was only one of many. Many are tied to Netanyahu's appointment of Ron Dermer as Ambassador in late 2013. Before Dermer emigrated to Israel he was literally a GOP operative in Washington. It's a way of approaching US politics he's continued as Israeli Ambassador. Obama's second term has also seen Netanyahu and members of his government taking an increasingly contemptuous stance toward Obama and increasingly open alliance with the GOP. I do not believe Israelis or many in the US foreign policy community grasp how much this has become the foundational political experience of Israel for many Democratic partisans, particularly younger Democrats.
Obama critics would say this hasn't been a one way street. The contempt is mutual. Certainly the contempt is mutual. I would say Netanyahu's interventions in US politics have been wildly more out of line than anything Obama has done. But it's sort of beside the point who started it. What we're talking about is the effect on the partisanization of the Israel-Palestine question in American politics.
Harder to gauge is the effect of the US's recent decision to allow a vote on settlements in the UN Security Council. For the purposes of this poll, I would say it is less the decision to allow the vote than the scalding response from the Israeli government which has openly accused Obama of lying, betrayal and openly embraced President-Elect Trump. A typical response came from close Netanyahu ally Miri Regev, the current Minister of Culture, who said of Obama: "He is history. We have Trump." Again, the issue here isn't which is more important or who 'started it'. It's which was likely to have had the bigger effect on Democrats' attitudes, default sympathies, toward Israel.
The resolution passed on December 23rd 2016 and the poll was on January 4th-9th, 2017. That blow up, and the vociferous response and alliance with Trump may actually be driving a lot of this since this poll was taken immediately after that happened and actually during some of it.
The best counter to my argument centered on Netanyahu is the Gaza War of 2014.
The Gaza War (called Operation 'Protective Edge' in Israel) was in the late summer of 2014 and sympathy for the Palestinians went up most between the July 2014 and April 2016 Pew polls. Again, from Pew: "The share of Democrats who say they sympathize more with Israel is down 10 points from April 2016. The share who say they sympathize more with the Palestinians is little changed from last April (29%), but is up significantly from July 2014 when just 17% said they sympathized more with the Palestinians."
But this is not the first big military conflict in Gaza. There was Operation 'Cast Lead' in 2008-09. There was Operation 'Pillar of Defense' in 2012. The 2014 conflict 'Protective Edge' was the biggest. But it was yet another blow up after others coming on a roughly two year cycle. Before that there were ferocious IDF incursions into the West Bank in the Spring of 2002 in response to the Second Intifada. There was the Second Lebanon War in 2006, though the nature of the coverage of Israeli-Lebanese conflicts is different from the Israeli-Palestinian ones and thus the effect on US public opinions likely different. In any case, wars between Israel and its neighbors are depressingly frequent. They have not effected US opinion this way in the past.
The big drop in sympathy for Israel - which does not clearly move in tandem with lack of sympathy for Palestinians - is over the last year, since April 2016, well after the 2014 War and the Netanyahu speech, again perhaps pointing to the fall out from the fight over the UN vote.
Supporters of the Palestinians love this new number for obvious reasons. Republicans also love it for very different ones. Many though certainly not all Democrats are likely chagrined by it - or at least the public perception of it. But it is unquestionable that it is a bad development for Israel. The partisanization of the US-Israel alliance is a great cudgel for the GOP. But it's bad for Israel since it portends an alliance which is hostage to partisan warfare in the United States rather than being stable and bipartisan over time.