“Any American Jew attending this rally is not a Jew—yes I said it!” So tweeted the Trump administration’s U.S. ambassador to Israel, David M. Friedman, about a rally and protest held in Washington, D.C. on Monday. “American Jews Say: CEASEFIRE NOW!,” the graphic promoting the rally read. “STOP GENOCIDE OF PALESTINIANS.” Monday’s protest—a rally at Farragut Square followed by a walk to the White House to disrupt business as usual—was organized by Jewish Voice for Peace, an anti-Zionist group, and IfNotNow, which describes itself as “a movement of American Jews organizing our community to end U.S. support for Israel’s apartheid...