Why did Israel need to pass the nation-state law? It’s a question worth pondering now that the shrieking accusations of its loudest bad-faith critics have been dispelled. The new law doesn’t state anything that the country’s Declaration of Independence had not already made clear, and it does not deprive a single individual of a single right. But why, precisely, was it necessary?It’s a complicated question that both the law’s supporters and its detractors haven’t gotten quite right. To claim, as Prime Minister Benjamin Netanyahu’s critics on the left do, that the law was all sound and fury, a piece of political theater designed to drum up fear and win votes, is to give the Israeli electorate, as world-weary a bunch as any, too little credit. To state, as some of the law’s supporters have, that without it Israel would be in some kind of existential danger of losing its Jewish particularity is to trade in the same histrionics as those who breathlessly argued that the law somehow heralded the end of Israel’s commitment to democracy. If you’d like a more nuanced view, all you have to do is look at this past weekend’s demonstration in Tel Aviv’s Rabin Square.Touted as a joint Arab-Jewish peace rally against the controversial law, the demonstration, according to reports in the Israeli press, drew upwards of 20,000 people. Some of them were waving Palestinian flags, which excited much media attention and drove the hottest of hotheads to portray everyone marching as a fan, if not an agent, of the PLO. The truth is more nuanced and more depressing: Even if the majority of the marchers did not partake in the chants, clearly heard in the square, to redeem Palestine “with blood and fire,” the spectacle was still a sordid one for the Israeli left, an ideological camp intent on completing its march towards political oblivion.The march was organized by the High Follow-Up Committee for Arab Citizens of Israel, a political organization serving as the umbrella group for all of the nation’s Arab parties. In 2006, the committee published a seminal document entitled “The Future Vision of the Palestinian Arabs in Israel,” thoroughly negating Israel’s right to define itself as a Jewish state. “Defining the Israeli State as a Jewish State and exploiting democracy in the service of its Jewishness excludes us,” read the document, “and creates tension between us and the nature and essence of the State.” But the committee, as the document makes clear, does not object to nationalism as such; while the rights of Jews, still the majority in the country, to chart their own course are decried as inherently oppressive, the rights of Arabs to pursue their national identity is presented as a basic human right. The document goes as far as advocating the immediate and unconditional return of all Palestinian refugees to their ancestral homes in Israel, which would mean the end of the Jewish state.Thankfully, most Israeli Arabs do not appear to share their leaders’ radical vision. Professor Sami Samocha, a sociologist at the University of Haifa and the most noted scholar of Jewish-Arab relations in Israel, has been conducting an annual survey of both groups’ attitudes since 1976; in 2015, he reported a moderate improvement, noting that Jews and Arabs alike were gradually viewing each other in more positive terms. This year, however, the results were far gloomier, with more than half of Israeli-Arabs refusing to acknowledge Israel as a Jewish state.What happened? The 2015 survey was conducted in the immediate aftermath of Operation Protective Edge, and so it would seem much more logical that emotions would run high following a violent confrontation between Israel and Hamas in Gaza. Why would so many who still felt cautiously optimistic then adopt a far thornier worldview in the course of three short years?This weekend’s march hints at an answer. Standing side by side with the High Follow-Up Committee and its representatives were prominent figures from the Israeli left, including representatives from the Meretz party and Amos Schocken, the publisher of Haaretz. Until not too long ago, Meretz used to be a liberal and Zionist party; I know, because I started out my political education as a member of its youth group. Recently, however, its spokeswoman, May Ossi, announced that changes were afoot: Meretz, she said, “is a non-Zionist Israeli political party, the party of all citizens because the very idea of Zionism necessarily erases an entire other people.” Schocken’s paper traveled a similarly troubling path, from a progressive publication committed to a Jewish and democratic state to a sensationalist promoter of anti-Zionist agitprop.It should come as little surprise, then, that Israel’s Arab population, observing this sea change in the Jewish left, felt compelled to follow suit and demand not a more equitable Jewish Israel but a non-Jewish Israel as its ultimate goal. And it should come as even less of a surprise that many Israelis, including a fair number of those who still define themselves as staunchly liberal, responded to this shift by lending their support to initiatives like the nation-state law.The overwhelming majority of Israeli Jews are still deeply committed to the Zionist idea, and see Israel as the historic homeland of the Jewish people. When the Jewish left—a political camp that had for decades embraced both Zionism and socialism without great difficulty and strove for justice without compromising its core values—abandoned its old affinities, this majority reacted by exercising its right for self-definition, a cornerstone of the democratic idea.It’s a pity that at the very moment when the nation’s Jews and Arabs alike would benefit greatly from moderation and reconciliation, the politics of radical chic triumphs and the breathless rhetoric of the extremes rings loudest. This weekend’s march makes it clear that the old Israeli left has concluded its historical mission; let’s hope it is soon replaced by a new and sensible force that once again picks up the age-old mantle and works to make the world’s sole Jewish state a more perfect place.