extends to lobbying for Hamas to crack down on jihadist groups that have been launching attacks on Israel, as Israel would like to see Mr. Morsi do, is not clear. But at the moment, the relative quiet out of Cairo is being viewed in Washington as a positive first step. "If Morsi wanted to use this for populist reasons, he'd be adopting a different posture," said Martin S. Indyk, the former American ambassador to Israel and the author of "Bending History: Barack Obama's Foreign Policy." "If he wanted to take apart the peace treaty, this is his opportunity," Mr. Indyk said. "The fact that he's not and is instead apparently working with President Obama to calm the situation is important." But Mr. Morsi's cooperation can only be counted on, another administration official said, so far as Israel does not invade Gaza, with the attendant civilian casualties. A ground war, the official said, "could mean all bets are off." I'm not going to tell you anything I know about this that has not been reported in the media. But you don't seek authority to call up 75,000 reserves at a huge cost to the economy if all you're going to do is send a few dozen pilots to hit a bunch of pre-selected targets.To put that number in perspective, only 10,000 troops were used in 2008's Operation Cast Lead . Though Iran would welcome the opportunity to demonstrate the spectrum of its militant proxy strength, especially after supplying Hamas with the