Welcome to Shavuot, the Most-Important-Least-Observed Jewish holiday. In a Torah-centered religion, celebrating the day the Jewish People received the Ten Commandments makes this holiday – perhaps more than Succot – “the” holiday. This is the fundamental one. And in a mission- driven nation built around the idea that belonging to our people means participating in a process of bettering ourselves individually and collectively to better the world, we should celebrate the day we received those marching orders. Moreover, Jewish Law equates Shavuot, one of the three pilgrimage festivals, with Passover and Succot.Yet, there it sits, neglected. Outside Israel, Shavuot lacks Hanukka’s Christmas-charged materialism, Passover’s democratic vibe, Yom Kippur’s masochistic solemnity, Rosh Hashana’s optimistic joy. It doesn’t even have Purim’s ribaldry or Succot’s booth-building. With non-Orthodox, non-Israeli life often reduced to Juvenile Judaism, a holiday of allnight study and cheesecake cannot compete. In Israel, of course, living by a Jewish calendar and having a day off makes Shavuot a national holiday. But despite more all-night learning festivals every year, it’s still mostly National Cheesecake-eating and Beach-Going Day.This neglect is particularly disturbing because the Jewish world desperately needs to learn Shavuot’s lessons about substantive learning, being Commanded, and staying unified.The first lesson is how essential Jewish literacy is to Jewish life – and how many Jews today are Jewishly illiterate. In his 2011 essay “Language, Identity, and the Scandal of American Jewry,” Leon Wieseltier analyzed American Jewry’s great crime. It’s not intermarriage, but ignorance. “The American Jewish community is the first great community in the history of our people that believes that it can receive, develop, and perpetuate the Jewish tradition not in a Jewish language,” he lamented. Noting that living in English condemns Jewish culture to being lost in translation, Wieseltier frankly predicted: “Without Hebrew the Jewish tradition will not disappear entirely in America; but most of it will certainly disappear.”Wieseltier was correct – and the illiteracy has worsened. The arrogant assumption when American Zionists come to Israel that Israelis will speak to them in English, treating the lingua franca of the Jewish world as English not Hebrew, once scandalized at least some. Today, it’s so normalized it’s barely noticed. The first challenge Jews should accept this Shavuot is committing to Jewish learning. In the Diaspora, it should start with a rededication to learning Hebrew, young and old alike.In Israel, they’ve mastered the Hebrew thing. But most Bible-quoting secular Zionists are long gone – even if a secular kid won this year’s Bible contest. Secular Israelis, too, should learn more about Judaism, about Jewish values, ideas, ideals and – the second challenge – demands.If Shavuot’s defining act is Moses receiving the Ten Commandments, modern American Jewry’s defining act has been rejecting the very notion of Commandments. The Union for Reform Judaism’s 2020 initiative endorses “Audacious Hospitality,” the “focused effort to embrace our diversity and reach out to those currently not engaged in Jewish life. The URJ believes that everyone can feel at home in Jewish community – and that Judaism must meet people where they are today to thrive tomorrow. As a movement, we stand for a Judaism that is inclusive and open – we believe that there is more than one authentic way to be Jewish.”Let’s face it, pluralism is a foreign policy. It sidesteps the big question. “If ‘everyone can feel at home in Jewish community,’ doesn’t it stop being a community?” Communities by definition need definition. The liberal American Jewish attempt to create communities without red lines, not on intermarriage or hostility to Israel or ritual observance or belief in God, is ideologically paradoxical – and unsuccessful. Jews are abandoning this spectral, watered down, I’m-ok-you’re-ok-I-stand- for-nothing-just-join-me approach.We need “Audacious Hospitality” accompanied by “Courageous Literacy” and some “Bold Boundaries.” There should be something that makes being Jewish Jewish – otherwise it’s just Jew-ish, a cutesy little affectation: an “oy” here, a memory there, but no depth, no meaning. Liberal Judaism won’t revive until it leaders learn the Ten Commandments’ essential lesson: you need guides, guardrails, standards – red lines – to make a community and perpetuate a tradition.At the same time, looking rightward, especially at the Israeli rabbinate, fanatics there are so busy drawing red lines they can’t see blue and white anymore. If the religious Left is too enamored of its pluralistic foreign policy it loses track of its self, the religious Right is so self-absorbed its foreign policy consists of offending, not teaching.Right-wing rabbis – especially the Israeli religious establishment – should undertake an honest damage assessment, estimating how many millions of Jews they have alienated over the years with harsh, unfeeling rules and by perpetuating a caricature of Judaism as unyielding that forgets that the Torah is a Tree Of Life – growing imperceptibly but gradually.Memo to the Orthodox Right: modernity happened. Most Jews don’t follow your interpretation. That should not lead you to dilute your approach. But, challenge yourselves: wherever you have the power to build blue-and- white consensus, consider how much you value the Jewish People, Jewish unity, a Jewish consensus – and ask: what are you doing to facilitate that? So let the debates begin. This Shavuot, let’s learn how to build a stronger, more united, Jewish community that restores that sense of Jewish wholeness we all shared at Sinai.The writer is the author of The Age of Clinton: America in the 1990s. His forthcoming book, The Zionist Ideas, which updates Arthur Hertzberg’s classic work, will be published by The Jewish Publication Society in Spring 2018. He is a Distinguished Scholar of North American History at McGill University. Follow on Twitter @GilTroy.