Republican National Committee Chairwoman Ronna McDaniel holds a gavel while speaking at the committee's winter meeting in Dana Point, Calif., on Jan. 27. (Jae C. Hong/AP) Analysis by Philip Bump ...

From the 1979 hostage crisis to support for Islamic militants, Iran has afflicted U.S. presidents. Now it’s testing President Joe Biden in the Israel-Hamas war, as well as in Ukraine.