“The real question is how much humble pie can Assad eat and still keep his svelte figure,” said Nathan Thrall, a Jerusalem-based analyst for the International Crisis Group, speaking of the Syrian president Bashar al-Assad. “The risks of action in Israel’s perception are lower today than they have been in the past. Everybody’s now testing each other and gauging what each one can get away with.”

Analysts said they did not see the airstrikes as the opening of a new war front, or as an attempt to prop up the Syrian rebels against the Syrian government of Mr. Assad. Rather, they tended to see it more as an extension of the long-running “shadow war” against Iran and Hezbollah, a tit-for-tat of terror attacks and assassinations that has stretched over decades and around the world.

“This shouldn’t be seen as Israel intervening on behalf of the rebels or against Bashar,” said Jonathan Spyer, a senior research fellow at the Interdisciplinary Center in Herzilya. “This is an escalation in a conflict we know about, and that is the conflict between Israel and Iran.”…

Israel may be banking on the idea that Hezbollah is saving its Iranian-provided firepower to attack Israel in retaliation for any Israeli or United States attack on the Iranian nuclear program.