The abandonment of the “no daylight” and “no surprises” principles climaxed over the Iranian nuclear program. Throughout my years in Washington, I participated in intimate and frank discussions with U.S. officials on the Iranian program. But parallel to the talks came administration statements and leaks—for example, each time Israeli warplanes reportedly struck Hezbollah-bound arms convoys in Syria—intended to deter Israel from striking Iran pre-emptively.

Finally, in 2014, Israel discovered that its primary ally had for months been secretly negotiating with its deadliest enemy. The talks resulted in an interim agreement that the great majority of Israelis considered a “bad deal” with an irrational, genocidal regime. Mr. Obama, though, insisted that Iran was a rational and potentially “very successful regional power.”

The daylight between Israel and the U.S. could not have been more blinding. And for Israelis who repeatedly heard the president pledge that he “had their backs” and “was not bluffing” about the military option, only to watch him tell an Israeli interviewer that “a military solution cannot fix” the Iranian nuclear threat, the astonishment could not have been greater.

Now, with the Middle East unraveling and dependable allies a rarity, the U.S. and Israel must restore the “no daylight” and “no surprises” principles.