As voters cast ballots in the Iowa caucuses Monday, many in the United States see this year’s presidential election as a test of American democracy. “I don’t know if in the coming years people will be looking at the United States as a model for democracy,” a second Arab diplomat warned. There’s a growing sense among foreign diplomats that moral or national security arguments — about defending a country unjustly invaded, deterring Russia, preventing a bigger war in Europe and safeguarding democracy — don’t work on the American far-right. The diplomats’ countries don’t always have the same interests. “We’ve gone from a unipolar world that we’re familiar with from the 1990s into a multipolar world, but the key pole is still the United States.