With his decision to boycott Sunday’s Israel Day parade, Mayor Mamdani has crossed a point of no return. Coming after his relentless criticism of Israel and recent embrace of the historically- inaccurate Palestinian version of the Jewish state’s creation, he is setting a dangerous new low at City Hall. As the first mayor in six decades to skip the iconic parade, his pattern of behavior reeks of antisemitism. He singles out Israel for vile attacks while otherwise steering clear of most international matters. He has said he would not visit Israel and pledges to arrest Prime Minister Benjamin Netanyahu if...