AP Photo

Benjamin Netanyahu was fuming. For the first time in months, the Israeli leader had allowed a discussion in his security cabinet about Iran’s nuclear program and it wasn’t going well. Several cabinet members were questioning the wisdom of defying the United States, Israel’s ally and protector, by weighing a strike on Iran before the American election in November, according to a source familiar with the details. The grinding back-and-forth went on for seven hours. When it came time for the security chiefs to weigh in, at least two of them disputed the premise Netanyahu had been advancing—that Israel’s window for an attack would last only through this year, before Iran moves its nuclear components to hardened sites underground. “You can interpret the intelligence in...