“It shall be the policy of the United States to combat anti-Semitism vigorously, using all available and appropriate legal tools, to prosecute, remove, or otherwise hold to account the perpetrators of unlawful anti-Semitic harassment and violence.” So states an executive order signed this week by President Trump, allotting all US department and agency heads 60 days to come up with meaningful new ways to fight the rise in anti-Jewish incidents in America. Should these officials need of inspiration, the order also refers to existing immigration laws, which permit the immediate deportation of any resident alien who “endorses or espouses terrorist...