N o president really wants to be compared to Jimmy Carter (rest his soul), but in Donald Trump ’s case, the parallels now are hard to ignore. Carter’s presidency was overtaken by a hostage crisis in Iran , where in 1979 followers of the Ayatollah Khomeini seized 66 Americans and held them (or most of them, anyway) for more than a year. The impasse played out as a televised drama — it gave rise to Ted Koppel’s  Nightline — and became entwined in the public mind with uncontrolled inflation, interest rates, and gas prices, while Carter pleaded with Americans to turn down their thermostats and put on sweaters instead. All of it signaled that the country was spiraling and the president overmatched. Almost a half century later, Trump stumbled into his own implacable hostage crisis in Iran, this one entirely of his own making. For several weeks, Iran has held the Straight or Hormuz — and, by extension, the global economy — at gunpoint.…