If Israeli leaders' bluster about Iran is, as it looks to many, a bluff aimed at pressuring the U.S., the next natural question is: What does Bibi Netanyahu want from Obama? At least one answer seems abundantly clear: "red lines." Another ask—and an altogether more daunting one—may have slipped out in an interview with Israeli Finance Minister Yuval Steinitz, a Netanyahu ally.

In an Israeli television interview, Steinitz said Netanyahu's position was that the international community "should set an ultimatum with a timeline" for Iran. The deadline he calls for presumably refers to demands that Iran comply with a handful of U.N. resolutions calling for suspension of its nuclear enrichment and accounting of alleged past weapons work, or else...