“It is hard to overstate the significance,” said retired Gen. David Petraeus, who oversaw the “surge” of American troops in Iraq in the violent years after the 2003 U.S. invasion. “But there will be responses in Iraq and likely Syria and the region.”…

“I can’t believe it,” one U.S. official said. “The immediate concern for me is: What’s the next step from Iran? Is this the beginning of a regional conflagration?”

A former U.S. official who dealt with the Middle East said the strike was especially notable because it targeted the leader of a state apparatus, as opposed to a non-state actor.

“We need to be prepared that we’re now at war,” he said.