Sen. Bernie Sanders has begun pushing the Democratic Party toward a platform fight over the Israeli-Palestinian conflict, a departure from his core focus on domestic economic issues that would put pressure on Hillary Clinton to handle a growing divide within her party.
The Democratic Party has long had a policy of support for Israel and its government, but consensus on that subject has frayed in recent years.
Four years ago, the floor of the Democratic National Convention erupted into boos after delegates, acting at the behest of President Obama, restored language to the party platform sought by backers of Israel. The language had been left out of an earlier draft, but White House officials wanted it restored to avoid alienating pro-Israel voters.
Since then, tensions between the administration and Israel have grown and so has unease among liberal Democrats about Israel's policies toward the Palestinians.
Many Democrats, including Obama, were angered last year when Republican lawmakers scheduled an address to Congress by Israeli Prime Minister Benjamin Netanyahu in which he denounced the administration's nuclear deal with Iran. The scale of civilian casualties in Israel's attack on Gaza in 2014 also alienated many liberals.
Despite those tensions, Clinton and many party leaders are loath to show any signs of weakening support for Israel, an ally that has long been central to America's Middle East policy and that has deep political support in the top reaches of both political parties.
Sanders, who is Jewish, spent months of his youth living on an Israeli kibbutz, but his views on the Jewish state reflect a socialist strain of Zionism no longer as prominent in Israel. He has spoken of seeking a more "evenhanded" treatment of Palestinians.
Sanders used his clout in nominating members to the party's platform drafting committee to select the president of an Arab rights organization and a campaign surrogate who accused Israel during the Gaza fighting of "a crime against humanity."
Sanders, in an interview with The Times on Wednesday, declared himself "100% supportive of Israel's right to exist." Israel, he said, has a right "to take all actions that are needed to protect itself from terrorism."
"But I believe that for too long our country and our government have not given the Palestinian people the respect that they need," he added. "Long term, if there's going to be peace in the Middle East, a lasting peace, the Palestinian people are going to have to be treated with respect and dignity."
Clinton advisors would not discuss the issue on the record because of sensitivity to any move that might inflame tensions with Sanders and his supporters. But the campaign suggested in a statement that she would resist changes that would upset stauncher backers of Israel.
"Hillary Clinton's views on Israel and the U.S.-Israel relationship are well-documented and she's confident that her delegates will work to ensure that the party platform reflects them," said Jake Sullivan, senior policy advisor.
Mark Mellman, a veteran Democratic strategist who also has worked in Israeli elections, predicted Clinton, as the party's nominee, would have her way, and that the platform would reflect her reputation in the Senate and as secretary of State as a strong backer of Israel.
But, he added, "that may require a little butting of heads."
A large majority of Americans strongly support Israel, according to polls, but the Democratic Party is increasingly torn over some of the actions of the Israeli government and how much sympathy to accord the plight of Palestinians.
Among self-described liberal Democrats surveyed in a Pew poll taken last month, 40% said they sympathized more with Palestinians than Israel, compared with 33% who sympathized more with Israel. Conservative Republicans, moderate/liberal Republicans, and moderate/liberal Democrats all showed far greater support for Israel, with conservative Republicans maintaining overwhelming sympathy for Israel at 79%, Pew found.
Pew has tracked the issue since 2001, and this was the first year that any of the four ideological groupings showed greater sympathy for Palestinians than Israel.
Sanders backers, by a small margin, also expressed more sympathy with the Palestinians than with Israel, the poll found. His campaign, a coalition of the party's left and independents, has paid heed to concerns from many liberals -- some of them Jewish -- that Palestinians have been marginalized in mainstream American politics and that criticism of the Israeli government is less tolerated here than it is even within Israel.
Last month, Sanders hired Simone Zimmerman, an outspoken young activist who opposes the Israeli occupation, as his Jewish outreach coordinator. She was quickly suspended amid intense criticism from Jewish organizations after it was revealed that she used profanity in Facebook posts about Netanyahu and Clinton. She could not be reached for comment.
"What we saw with the suspension of Simone was a demonstration of how far our community and the political community has to go on this issue," said Yonah Lieberman, who like Zimmerman is a member of a group called IfNotNow. Members of the group were arrested last month for staging occupations of the offices of Jewish organizations in an effort to prod them to push for changes in Israel's policies.
Party platforms are seldom read unless they are the subject of controversy, as the Democratic document was four years ago. But advocates on both sides care deeply about the nuances in them.
Sanders won added clout in writing the platform when Democratic Party officials agreed to allow him to name five of 15 members of the drafting committee. Clinton's campaign got six appointments, and four are controlled by the party. Sanders will not have a majority but does have enough of a presence to wage high-profile debates if he chooses. His campaign has not made clear yet what he will ask for.
One Sanders appointee, Cornel West, a Princeton University philosophy professor, has been especially provocative to pro-Israel voters, referring in a 2014 Facebook post to "the Israeli massacre of innocent Palestinians, especially the precious children."
"The rockets of Hamas indeed are morally wrong and politically ineffective – but these crimes pale in the face of the U.S. supported Israeli slaughters of innocent civilians," West wrote of the 2014 military operation.
Israeli officials said the attacks were necessary to stop rocket attacks by Hamas, the radical Palestinian group that controls Gaza, a small coastal enclave sandwiched between Israel and Egypt.
Another Sanders appointment went to James Zogby, a longtime Democratic insider who heads the Arab American Institute.
In an interview, Zogby said he is not looking for a fight, but does believe the platform needs to reflect what he called a broader American consensus on acknowledging the needs of both peoples.
"That's where the numbers are, and while people are very supportive of Israel, they are not so supportive of various policies supported by Israel," he said.
If Clinton does agree to significant changes in the platform, Republicans will be lying in wait.
"If you're pro-Israel, the warning lights are flashing red right now," said Ari Fleischer, a former press secretary for President George W. Bush.
But the issue is not easy for Republicans either. Donald Trump has given conflicting remarks about treating Jerusalem as Israel's capital and has also called, at times, for more neutrality in the Palestinian dispute. Fleischer, a board member of the Republican Jewish Coalition, says he is voting for Trump but will keep an eye on him.
Fleischer views Clinton's record on Israel as mixed, citing her support for the Iran nuclear deal as an example. Trump has tried to reassure Israel supporters with a strong speech to the American Israel Public Affairs Committee, he said.
"He began from a position of weakness but he has since changed his tune," Fleischer said.
The current Democratic platform language, which, among other things, refers to Jerusalem as Israel's capital, offers important symbolism, but is not reflected in U.S. policy. Since Israel captured all of Jerusalem in 1967, U.S. policy has been that its status is a subject for peace negotiations among Israel and its Arab neighbors.
"It is meaningful in the optics," said Sarah E. Yerkes, a former officer in the State Department Office of Israel and Palestinian Affairs, now a visiting fellow at the Brookings Institution. "If the platform were to say that 'Jerusalem could be a capital of a future Palestinian state,' that would be a big red flag to Israelis."
The platform is expected to be the subject of intense lobbying, both directly and indirectly, from Israel's supporters.
"We are watching every word, and it makes a big deal in Israel," said a former Israeli diplomat who requested anonymity because of the sensitivity in discussing American domestic politics.
"It will not change quietly," the former diplomat said. "I don't think it will change because there are so many friends of Israel within the Democratic Party and the Republican Party."