WHAT MAKES SOMEONE A JEW—not just a Jew in name, but a Jew in good standing—today? In Haredi circles, being a real Jew means adhering to religious law. In leftist Jewish spaces, it means championing progressive causes. But these environments are the exceptions. In the broad center of Jewish life—where power and respectability lie—being a Jew means, above all, supporting the existence of a Jewish state. In most Jewish communities on earth, rejecting Israel is a greater heresy than rejecting God.