Why Tensions Are Climbing Between Israel and the U.S.

U.S.-Israeli relations had been surviving a spring and summer of exceptional strains pretty well.

Until now, that is. Suddenly, serious stress fractures are opening up as the Israeli operation against Hamas in the Gaza Strip enters its third week—and they figure to get worse before they get better.

The clearest sign came Sunday, in the form of what might have seemed just another pro forma White House statement, describing a call between President Barack Obama and Israeli Prime Minister Benjamin Netanyahu. Those two leaders have a relationship filled with all...