Donald Trump's position on Middle East issues indicates not so much a structured vision, with strong and weak points, as a troubling inability to choose between alternatives and make decisions. From this standpoint, the "Muslim Ban" soap opera is as disconcerting as the absence of any methodical plan to fight ISIS, or the escalating turmoil in Yemen. Above all, the question of the location of the US embassy in Israel - during his campaign Trump promised to move it to Jerusalem - will be a test that might trigger shock waves and upset the network of American alliances in the region. Beyond the Israeli-Palestinian issue, Trump could rapidly come face-to-face with reality in Syria, Iraq, Yemen or Libya.