JERUSALEM — Prime Minister Benjamin Netanyahu of Israel, in the middle of a re-election campaign, seemed set to score back-to-back diplomatic triumphs in a span of just a few days, with Poland, of all countries, playing an important role in both. This past week, Mr. Netanyahu attended a meeting in Warsaw, convened by the Trump administration, where five dozen nations discussed the common strategic threat posed by Iran. Sunni Arab nations were also at the conference, and Mr. Netanyahu made the most of it, appearing behind closed doors alongside diplomats from Saudi Arabia, Yemen and Bahrain and later leaking a…
