ELIOT COHEN: A Reckoning for Obama’s Foreign-Policy Legacy. “Veterans of the last administration are learning a hard lesson: Policies constructed by executive order and executive agreement are just as easily blown up by them.”

The Iran deal was, in truth, a very bad one. It did nothing to inhibit Iranian behavior in the broader Middle East, did nothing to stop its ballistic programs, and opened the path for a resumption of the nuclear-weapons program in a decade or so. Some of us said so at the time. Walking away from it, however, will make matters worse not only because success is unlikely, but because this shredding of an earlier presidential agreement further undermines the qualities that those who look to American leadership have come to value — predictability, steadiness, and continuity. Even when American allies have doubted the superpower’s wisdom, they usually felt they could count on its constancy.

Predictability in being taken for a sucker is no virtue, and tearing up treaties the Senate rejected is no vice.