In a society built on the free exchange of ideas, as Walt and Mearsheimer point out, one answer can be found by looking at the many self-appointed gatekeepers, such as Abraham Foxman and the Anti-Defamation League, or Harvard law professor Alan Dershowitz, who use their Jewish identity as both a shield and cudgel. They work diligently to silence those who question ill-conceived policies of the Israeli and U.S. governments. Non-Jewish critics, even former President Carter, are denounced as anti-Semites. Special ire is reserved for Jewish dissenters, who are branded as “self-hating” or “marginal,” while Muslim and Arab-Americans are easily smeared...