There are certain international crises that on their face demand the immediate and urgent attention of presidents. We all know them when we see them -- and so does the man in the White House. Saddam's invasion of Kuwait comes to mind -- an easy call. But there are other situations where the call may be tougher to make. Bosnia got a president's attention; Rwanda did not. And what about Syria -- now in the midst of a civil war and humanitarian crisis of enormous proportions. Certainly there are U.S. interests at stake, but are they vital interests? And what of President Obama's response so far: it has been deliberately limited, but should he go further, and with what sorts of options? Military intervention? Something else? Something less? One thing is certain: Syria is not one of those easy calls. It's what we're debating in Aspen, when we take on the topic: The U.S. has no dog in the fight in Syria.