Iran-Backed Militias in Baghdad Present a Test for Biden

Stephen Troell, a U.S aid worker from Tennessee, was shot dead by unknown assailants while he drove through Baghdad last week with his wife and daughter in the car. A little-known militia claimed responsibility for the murder, calling it revenge for the U.S. airstrike that killed Iranian Maj. Gen. Qassem Suleimani more than two years ago. Troell’s death is a test of whether President Joe Biden is prepared to hold Iran’s clerical dictatorship accountable for the killing or attempted killing of American civilians—a test he has failed before.

In August,...