I love the new Jerusalem train. When visitors to Israel ask me what to do here, I tell them: Ride the light rail. It's a model of coexistence, Jerusalem style, I explain. Jews and Arabs, ultra-Orthodox and Russians: Everyone crammed together in unhappy proximity, yet making the best of it and getting on with their lives. But not always. Late one night – it happened to be the eve before Tisha B'Av, the fast day commemorating the destruction of the Temple and Jerusalem – I took one of the last trains from the city center to French Hill, my neighborhood in north Jerusalem. As the train pulled into my station, there were shouts from the back. I couldn't tell what was happening and got off.My streets. I was driven to a police station to give testimony. In the car a cop – an Arab, probably a Druse –admitted to me, “If you hadn’t stepped forward, we would have arrested the Arabs. In most of these situations, it’s usuallly the minorities who attack Jews.” “Minorities” is polite Hebrew for Arabs. I gave my testimony and was driven home. It was 2 AM, less than 24 hours before Tisha B’Av. So much for the story. No mention of the incident appeared in the media. It was, after all, a minor event. No one was seriously hurt. But perhaps the real significance of the event lies elsewhere. My confrontation with the Jewish zealot was also a philosophical argument – not only an obvious clash over radically different perceptions of Jewish ethics, but over the responsibilities imposed by Jewish sovereignty. When the young man told me in so many words that I was a traitor to my people, he was faulting me for placing Western democratic norms over his understanding of Jewish law. Not only was I turning him, a fellow Jew, over to police – some of whom weren’t even Jews! – but I was abandoning a sister in spiritual crisis. One unintended consequence of Zionism is that, in creating a state that was not only Jewish but democratic, it placed necessary limits on Jewish solidarity. As an Israeli, I have responsibility not only to my fellow Jews but also to my fellow Israelis, whether or not they are Jewish. And I have responsibility to those who live among us who don't have Israeli citizenship but are dependent on the fairness of the state's institutions. Sometimes those multiple levels of responsibility conflict. There is a deeper problem here than the violence of a fanatical fringe. Large parts of the Orthodox community haven’t yet internalized the hard but essential price of Jewish sovereignty. That price is the need to respect the primacy of democratic rules in the public space, even if that means restricting how one’s notion of Jewish law should govern that space. For the young Jewish assailant, the need to “save” a Jewish young woman from her Arab boyfriend was an overriding religious imperative. One can argue with his understanding of Jewish law – and that is an argument that must be vigorously engaged. But in one sense that argument is irrelevant: In the rules of a democratic public space, a young person’s partner is no one’s business but her own. Ignore those rules and the result is anarchy. Hurban habayit – the destruction of the Jewish national home. The streets of Jerusalem seem increasingly threatened with anarchy. During the same week that the incident occurred at the French Hill train station, several haredi soldiers in uniform were attacked by extremist haredim in the Mea Shearim neighborhood, where posters compare haredim who serve in the IDF to insects. As the fast of Tisha B’Av was ending, a haredi was repeatedly stabbed outside the Damascus Gate, presumably by Palestinian terrorists. Multiple struggles are being fought to keep Jerusalem a safe, open and pluralistic city. A city that belongs to all of its residents, to Jews of every religious denomination and no denomination, to those from any faith who love and revere her. However weary one often feels from the pressures of living here, I am grateful for the privilege of being a custodian of Jerusalem, of taking responsibility for the future of this city, for the quality of our public space. That, after all, is what it means to be a sovereign people in its land. Yossi Klein Halevi is a senior fellow and member of the iEngage Project research group of the Shalom Hartman Institute. He is author of the forthcoming book, Like Dreamers: The Story of the Israeli Paratroopers Who Reunited Jerusalem and Divided a Nation (HarperCollins, October, 2013).So did the group from the back of the train. A young man in a large knitted kippah lunged at a young Arab man, kicking and swinging. A young woman who was with the Arab young man shouted in Hebrew, “Leave us alone!” The Arab tried to back off. His main concern seemed to be to protect the young woman beside him. I stood before the Jewish attacker. “Calm down,” I said."How can I calm down?” he shouted at me. “He's taking our sister to his apartment to rape her!" So that’s what this was about. Protecting the purity of the nation. I called the police. We’re already on our way, I was told. Hurry, I said, there could be blood here. A group of Jewish teenagers, mostly haredim, gathered. “Leave our sister alone!” one of them shouted. Meanwhile several Arab teenagers approached, trying to protect the couple. There was scuffling. The haredim began chasing the couple. I ran after them. Someone sprayed Mace in my eye. Police came. The couple slipped away. The Arab young men retreated to the far end of the station. A haredi teenager pointed toward them: "They attacked a Jew!" he said. The cops ran toward the young Arabs. I ran after them. “I’m a witness!” I shouted. “Jews attacked an Arab.”One of the cops stopped and asked if I can identify any of the assailants. I saw the young man in the big knitted kippah who had started the incident. He was now calmly crossing the street, just another innocent passerby. “Him,” I said to the cop. “You sure?” “A hundred percent.” The young man was handcuffed and brought to me for face to face identification. “That’s him,” I confirmed. He looked at me – a fellow Jew in a kippah – more with contempt than hatred. He had tried to perform a mitzvah, a religious obligation, and I had betrayed him. “Kol hakavod,” he said to me sarcastically, Well done. Then he cursed me, or perhaps threatened me: “You’ve lost the world to come – and also this world.”“I won’t let you do a pogrom in the streets of Jerusalem,” I replied.