The Hamas terrorist attacks on Israel and Israel’s retaliatory strikes on Gaza are creating a fissure between Democratic constituencies crucial to President Biden’s campaign for a second term in the White House.The Nov. 2 Quinnipiac University Poll found that half of all voters approved of the way Israel is responding to the Oct. 7 attacks, while 35 percent disapproved. Among all voters, however, one key subgroup dissented — 18-to-34-years-olds — a constituency that provided Biden with enough votes in 2020 to put him over the top. These young voters faulted Israel’s response to the attacks, 52-32 percent.Exit poll data from 2020 shows that Donald Trump beat Biden by small margins among the 60 percent of the electorate that was 45 or older, that Biden won 52-46 among the 23 percent of voters aged 30 to 44 and that the one bloc decisively in favor of Biden was voters aged 18 to 29, who made up 17 percent of the electorate and backed the Democratic nominee 60-36.Perhaps equally significant, in March 2023, more than six months before Hamas’s attack on Israel, Gallup found that “sympathy toward the Palestinians among U.S. adults is at a new high of 31 percent, while the proportion not favoring either side is at a new low of 15 percent. The 54 percent of Americans sympathizing more with the Israelis is similar to last year’s 55 percent, but it is the lowest since 2005.”This shift in American public opinion toward Palestinians provides crucial insight into what my Times colleagues Jennifer Medina and Lisa Lerer wrote on Oct. 20:Progressive Jews who have spent years supporting racial equity, gay and transgender rights, abortion rights and other causes on the American left — including opposing Israeli policies in Gaza and the West Bank — are suddenly feeling abandoned by those who they long thought of as allies. This wartime shift represents a fundamental break within a liberal coalition that has long powered the Democratic Party.There is, Medina and Lerer add:a politically engaged swath of American Jewry who are reaching a breaking point. They have long sought an end to the Israeli government’s occupation of the West Bank and blockade of Gaza, supported a two-state solution and protested the right-wing government of Benjamin Netanyahu.But in the Hamas attacks, many saw an existential threat, evoking memories of the Holocaust and generations of antisemitism, and provoking anxiety about whether they could face attacks in the United States. And they were taken aback to discover that many of their ideological allies not only failed to perceive the same threats but also saw them as oppressors deserving of blame.Bruce Cain, a political scientist at Stanford, replied by email to my question on the domestic political consequences of the violence in the Middle East:For Democrats, the Gaza war exacerbates pre-existing coalitional tensions along age, racial, religious, and ideological lines. The pro-Hamas faction is younger, nonwhite, Muslim and secular, and more progressive. The pro-Israel faction is older, whiter, Jewish and Christian, and more centrist.Biden cannot afford to lose even thin slices of the Democratic electorate, Cain argued: “As the Siena/NYT poll indicates, small swings in turnout of the Democratic base can doom Biden. This is what happened to Hillary behind the blue curtain in 2016.”“The longer and bloodier the war,” Cain added, “the harder it will be for the Democratic coalition.”I asked Norman Ornstein, a senior fellow at the American Enterprise Institute, “Do you see the conflict hurting Biden’s prospects or helping them?” He replied by email: “Right now, there is no question it is dividing the Democratic base and hurting Biden’s approval.” But, Ornstein quickly added, “the election is a year away, and, more important, all will be shaped by the outcome of the conflict.”Biden’s support of Israel has produced exceptional, if not unprecedented, dissent among party loyalists and government employees.On Nov. 3, Liz Skalka, Daniel Marans and Akbar Shahid Ahmed reported on the HuffPost website that more than 50 staff members of the Democratic National Committee had signed a letter calling for a cease-fire in Gaza.“As strategic partners to the administration … we feel it is the D.N.C.’s moral obligation to urge President Biden to publicly call for a cease-fire,” they wrote. “With the number of civilian deaths growing rapidly each day, we must be clear: the Israeli government’s unrelenting military bombardment and blockading of vital supplies entering Gaza must end.”Along similar lines, a Nov. 1 Foreign Policy article by Robbie Gramer disclosed that there was a “storm of dissent brewing in the State Department.”A group of State Department employees opposed to administration policies is gathering signatures for a “dissent cable,” Gramer wrote, a formal procedure created by the State Department “to allow its users the opportunity to bring dissenting or alternative views on substantive foreign policy issues.”Gramer reported that “many U.S. diplomats were privately angered, shocked and despondent by what they perceived as a de facto blank check from Washington for Israel to launch a massive military operation in Gaza at an immense humanitarian cost for the besieged Palestinian civilians in Gaza.”In a separate Nov. 3 Foreign Policy article, “More U.S. Officials Are Anonymously Calling for a Gaza Cease-Fire,” Amy Mackinnon and Gramer wrote:Hundreds of USAID (United States Agency for International Development) officials have reportedly signed a letter calling on the Biden administration to push for “an immediate cease-fire and cessation of hostilities” in the Israel-Hamas war, according to a copy of the petition obtained by Foreign Policy.On Nov. 3, 56 Democratic members of the House and two senators wrote to Antony Blinken, the secretary of state, demanding that the administration “make clear that Israel must conduct military operations within the scope of international law and minimize civilian harm.”“We must continue to hold ourselves and our closest allies to the highest standards of conduct,” the authors of the letter went on to say,even at times of great tragedy and violence. While we firmly believe in Israel’s right to defend itself, we are gravely concerned by Israel’s military operation and conduct that fails to limit harm to noncombatants and vulnerable populations. Nearly 9,000 Palestinians have been killed, including over 3,600 children. Abiding by international law is not only morally imperative, but also legally required per international humanitarian law, and strategically important to prevent regional escalation and to preserve global support for Israel’s response to Hamas’s attack.One underlying reason the Israel versus Hamas conflict — including both the Oct. 7 terrorist attacks by Hamas on Israel and the subsequent Israeli counterattack on Gaza — is particularly problematic for Democrats is that psychological research shows that liberals are more inclined to feel empathy than conservatives.In a May 2018 paper, “Are Liberals and Conservatives Equally Motivated to Feel Empathy Toward Others?” Yossi Hasson, Maya Tamir, Kea S. Brahms, J. Christopher Cohrs and Eran Halperin reported that “on average and across samples, liberals wanted to feel more empathy and experienced more empathy than conservatives did.”Their conclusion found support in a paper that was published in May, “Ideological Values Are Parametrically Associated With Empathy Neural Response to Vicarious Suffering,” by Niloufar Zebarjadi, Eliyahu Adler, Annika Kluge, Mikko Sams and Jonathan Levy of Aalto University in Finland. The five authors used neuroimaging “to reveal an asymmetry in the neural empathy response as a function of political ideology.”The research by Zebarjadi and her four colleagues “revealed a typical rhythmic alpha-band ‘empathy response’ in the temporal-parietal junction. This neural empathy response was significantly stronger in the leftist than in the rightist group” of those studied.Jeremy Konyndyk, who served as the director of USAID’s Office of U.S. Foreign Disaster Assistance from 2013-17, gave voice to this empathy in an interview with Politico about the Israel/Hamas conflict:What the rest of the world sees is that when civilian apartment buildings are bombed by Russia in Ukraine, the U.S. government forcefully condemns this as illegitimate. And when they see similar tactics being used by the I.D.F. in Gaza, they see lock-step support from the U.S. government. This dramatically undermines the credibility of international humanitarian law.The fundamental foundation of international law is that certain things are wrong full stop because it happens to humans. That’s why it makes the attacks by Hamas wrong — deeply horrific and a grave violation of international humanitarian law. And that’s why it makes war crimes in response wrong.One of the striking findings in polling conducted in the aftermath of Oct. 7 is how much more supportive young voters are of Hamas and how much less supportive they are of Israel.The Oct. 19 Harvard-Harris poll asked 2,116 registered voters: “In general in this conflict do you side more with Israel or Hamas?”By 84 to 16 percent, voters chose Israel, with everyone 25 or older backing the Jewish state by three to one or better. The one exception was voters 18 to 25, with 52 percent saying they sided with Israel and 48 percent with Hamas.Asked “Do you think the Hamas killing of 1,200 Israeli civilians in Israel can be justified by the grievances of Palestinians or is it not justified?” an overwhelming majority of registered voters surveyed, 76 percent, said it could not be justified; 24 percent said it could be.Among the youngest voters, however, 51 percent of those 18 to 24 said the killing “can be justified by the grievance of Palestinians” and 49 percent said it cannot be. Voters 25 to 34 were split, 48 percent saying the killing of Israelis can be justified, 52 saying it cannot.In researching their March 2022 article, “The Young American Left and Attitudes About Israel,” Laura Royden and Eitan Hersh, political scientists at Harvard and Tufts, “surveyed 3,500 U.S. adults, including oversampling of 2,500 adults aged 18-30” to explore why “young people and the ideological far left have developed distinctly negative views toward Israel.”“In June 2021,” they write, “immediately following armed conflict in Israel and Palestine, liberal Democrats were three times more likely than conservative Republicans to say that the U.S.A. was too supportive of Israel. Three in five Republicans, but only one in five Democrats, agreed in May 2021 that it was very important for the U.S.A. to help protect Israel.”Among Democrats aged 18-35, however, they found that “respondents were three times more likely to say the U.S.A. should lean more toward Palestinians than Israel.”Digging deeper, Royden and Hersh found a clear ideological and age pattern:On both ideological extremes, more young adults than older adults hold an unfavorable view of Israel. Moderate young adult favorable attitudes toward Israel (58 percent) is indistinguishable from moderate older adults (at 62 percent). The difference is largest on the far left, where Israel favorability is 27 percentage points less among younger very liberal adults (at 33 percent) for young adults compared with older adults (at 60 percent). Young very conservative adults are supportive of Israel (66 percent), but substantially less so than older very conservative adults (82 percent). Clearly, the most left-leaning young adults have the lowest rating of Israel.If many young people are disaffected with the Biden administration’s handling of the conflict between Hamas and Israel, their discontent pales in comparison with that of Muslim and Arab Americans.The Arab American Institute commissioned John Zogby Strategies to conduct a survey of 500 Arab Americans between Oct. 23 and Oct. 27. For Biden, the results were striking: “Support for President Biden in the upcoming election has plummeted among Arab Americans voters, dropping from 59 percent in 2020 to 17 percent, a 42-point decrease.”Two-thirds of Arab Americans “have a negative view of President Biden’s response to the current violence in Palestine and Israel,” according to the poll. “A strong majority of Arab Americans believe the U.S. should call for a cease-fire on the current violence.”In terms of partisan identification, Zogby wrote in his summary, the surveymarks the first time in our 26 years of polling Arab American voters in which a majority did not claim to prefer the Democratic Party. In 2008 and 2016, Democrats outnumbered Republicans by two to one. In this poll, 32 percent of Arab Americans identified as Republican as opposed to just 23 percent who identified as Democrats.In 2020, Biden carried Michigan by 154,181 votes. Arab Americans played a significant role in his victory there.Farah Pandith, a senior fellow at the Council on Foreign Relations, pointed out in an email that until recently, Muslim Americans had become a core Biden constituency:In 2020, American Muslims were involved in fund-raising and volunteering in the Biden campaign. They were mobilizing themselves to get Muslims out to vote, to educate and to — importantly — be publicly seen doing so. With so much hardship in the years post 9/11 and accusations that American Muslims could not be loyal Americans and practicing Muslims, this dedicated effort is compelling. These generations not only wanted to debunk that false narrative, but they wanted to see their candidate win — believing that Biden would understand their lived experience in America in a post 9/11 world and govern accordingly.Now, Pandith wrote, “it is clear that the hard-won trust and warm relationship Biden enjoyed with the vast number of American Muslims has been diminished. For many, their confidence in and loyalty to Biden has seemed to evaporate.”I asked a political operative closely tied to the Biden campaign — who insisted on anonymity in order to speak forthrightly — about the ramifications of the struggle between Israel and Hamas:There are open wounds and we are far from the war’s end. And there are hostages still out there. And Americans both tire and get bored with foreign conflicts after the messy part is done. But I do know one thing: Trump was the president of the Muslim ban and he called for a Muslim ban 2.0, so I don’t think a lot of Arab Americans are going his way. I think there is time for Biden to get them back. Not all of them.Julie Wronski, a political scientist at the University of Mississippi, argued by email that concern over Biden’s problems in dealing with the Mideast conflict may be overblown:Americans traditionally do not hold consistent or well-informed opinions on foreign policy. The further a foreign conflict or global issue is removed from people’s day to day lives, the less they are going to hold any meaningful opinion about it or use it to guide their political preferences.In addition, Wronski continued, “the role of negative partisanship may outweigh Muslim Americans’ criticisms of Biden’s foreign policy.” Some voters may defect to a third-party candidate or abstain from voting, but “a potential second Trump term can be more threatening to Muslim Americans domestically, given Trump’s record and rhetoric toward minority and marginalized groups, than Biden’s foreign policy agenda.”I asked Stephen Ansolabehere, a professor of government at Harvard, for his perspective. He replied to my query by email:My sense right now from our data is that Biden is in a very complicated political situation. Jewish voters, while only 2 percent of the electorate, provided key support (and voted about 70 percent for Biden) in pivotal states, where every group counts. Biden did even better among Muslim voters, winning 90 percent of the vote. Muslims are only about one-half of one percent of the electorate. Both groups are small shares of the overall vote, but they both vote Democratic. Biden risks alienating one Democratic group or the other if this is not handled right.Above all though, the situation in the Middle East is terrible. It is a human tragedy. Every president in modern history has tried to find a resolution to the Israel-Palestine question. Biden now faces the task of containing this conflict so that it does not escalate into a broader Middle East war. There’s not much upside here, politically or morally, just avoiding potentially terrible outcomes.The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More