Midway through Barack Obama’s first term as president, U.S. officials grew alarmed that Israel might launch a unilateral air strike against Iran’s nuclear program. Iran had snubbed Obama’s outreach after the 2008 election, and rejected an October 2009 international proposal to ship most of its enriched uranium out of the country—stirring pessimism about prospects for a future breakthrough.

“Militarily, I thought we needed to prepare for a possible Israeli attack and Iranian retaliation,” former Defense Secretary Robert Gates writes in his new memoir, Duty. At a January 2010 Oval Office meeting, Gates told Obama “he needed to consider the ramifications of a no-warning Israeli attack,” including whether the U.S. would assist Israel and how it would respond to Iranian retaliation.

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Around the same time, senior officials met to discuss ways the U.S. might dissuade Israeli Prime Minister from taking unilateral action. In one such meeting, Secretary of State Hillary Clinton raised a bracing question, two former Obama administration officials tell TIME: Was it possible that, instead of trying to restrain Israel, the U.S. should instead provide what one of those official described as “a tacit green light to the Israelis to take care of the problem for us”? In other words, instead of begging Israeli Prime Minister Benjamin Netanyahu to give diplomacy more time, perhaps it was worth telling him to go proceed with airstrikes.

Clinton did not actually endorse the idea. She only raised the notion “as one option to consider,” according to one former official, who adds that it gained no traction inside the administration. Clinton’s current press secretary, Nick Merrill, did not respond to requests for comment this week on this matter.

While the very idea of a U.S.-approved Israeli strike on Iran is dramatic, Clinton’s thought experiment was actually a responsible act of bureaucratic deliberation, says Kenneth Pollack, a former White House national security aide under Bill Clinton and author of a recent book on Iran.

“Anytime something like that comes up, you need to discuss it—and in fact it’s irresponsible not to,” says Pollack, who adds that he personally thinks a unilateral Israeli strike should be resisted. “Sometimes you just want to look at it, and if you decide it’s a bad idea, that allows you to make the case against it more effectively. So it leads to a much better policy process in which you can figure out what to do instead.”

Obama continues to pursue diplomacy with Iran. And Israel continues to hold its fire, however grudgingly.

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