Mr. DeSantis never once mentioned the progressive Democrats who have said they will boycott a speech by Mr. Herzog to a joint session of Congress on Wednesday. But he used his speech to emphasize his strong support for Israel and attack White House policies, as many conservatives have sought to portray Democrats who criticize Israel as anti-Zionist or even antisemitic. The moment is an uncomfortable one for both parties. Antisemitism has been on the rise in recent years. Robert F. Kennedy Jr., a long-shot Democratic presidential candidate, has been invited by House Republicans to testify on Capitol Hill on censorship....