What would trigger US strike in Syria? Mixed messages from DOD

U.S. military officials gave varying – and at times confusing -- explanations Monday for what, if anything, would trigger U.S. airstrikes against Islamic State targets in Syria, after the Joint Chiefs chairman indicated he’s not yet ready to authorize such a strike.

On Sunday, Joint Chiefs Chairman Gen. Martin Dempsey appeared to tone down remarks he made last week about the growing terror network that’s taken root in Iraq and Syria.

Dempsey, speaking to reporters on board a military plane traveling to Afghanistan, said he believes the Sunni insurgent...