Joint Chiefs of Staff Chairman Gen. Martin Dempsey testifies during a hearing on intervention in Syria before the House Foreign Affairs Committee on September 4, 2013. Alex Wong/Getty Images

When asked by Senator Bob Corker (R-TN) during Senate testimony on Tuesday what the United States is "seeking" in Syria, Gen. Martin Dempsey had nothing to say. "I can't answer that, what we're seeking," he replied. Secretary of State John Kerry jumped in to answer for Dempsey, but the Joint Chiefs of Staff Chairman's response to the senator's question was noted, approvingly, by many at the Pentagon as something less than an endorsement of President Barack Obama's Syria policy. If Obama orders the military into action in Syria, the response will be unflinching. But there's a discernible discomfort among recently retired generals and military intellectuals, echoed more quietly within the serving ranks, over fighting "wars of choice." Then-Defense Secretary Robert Gates expressed this disquiet during a widely circulated address at West Point in April of 2008, when he cited the three axioms taught by legendary military tutor Maj. Gen. Fox Conner to guide decisions about when the U.S. should go to war: The U.S., Conner had said, should never fight unless it has to, never fight alone, and never fight for long. It's not known whether "Marty" Dempsey, as he is known within the top brass, embraces Conner's principles, but it's clear that he's quietly asking the same questions over intervention in Syria: Is this war absolutely necessary; will we have to go it alone; and when does it end? They're good questions, although Dempsey's senior colleagues and close friends say his cautious counsel isn't being sufficiently heeded in the White House.

The interventionists had no answer for the question, "And then what?"

Dempsey wasn't Barack Obama's first choice to succeed Adm. Mike Mullen as Chairman of the Joint Chiefs. That would have been Marine Gen. James "Hoss" Cartwright, the then-J.C.S Vice Chairman whose nomination was derailed by allegations (of which he was later cleared by a Pentagon Inspector General's report) of an inappropriate relationship with a female aide. That brought Dempsey into the picture, to the surprise of many in the ranks -- and the alarm of some who feared he'd be overly deferential to the president. But the recently retired senior officer pointed to Dempsey's Syria testimony to counter the view that the Chairman would be a pushover for the White House. "You can be sure that his buddies on the J.C.S. don't see it that way," the officer says. "They're cheering him on." Not only are the military's top officers wrestling with looming budget cuts, they view Obama's appointment of Susan Rice as his national security adviser and Samantha Power as U.S. ambassador at the U.N. with skepticism. Both officials are well known advocates of sending the U.S. military to stop humanitarian crises around the world, a principle that arouses little enthusiasm among the top brass. The most recent humanitarian intervention, in Libya, is used by many in the military to question whether intervention in Syria is wise, or necessary. These senior military commanders point to the Libyan outcome -- rather than the October 1998 NATO humanitarian intervention in Kosovo, which Pentagon conventional wisdom deems a success -- as an example of the risks posed by intervention in Syria. Libya sparked a series of unintended security consequences beyond Libya's borders that America and its allies have had to live with ever since, and the regional stakes are far higher in Syria. The military leadership had quietly opposed NATO's Libya intervention, standing behind then-Secretary of Defense Robert Gates's argument that the interventionists had no answer for the question, "And then what?" Some currently serving officers say Gates was right on Libya. In the wake of Muammar Gaddafi's overthrow, extremists seeded instability in Mali, where French troops were required to prevent the West African country from being overrun by al-Qaeda inspired militias, boosted by weapons looted from Libya's armories.

While the military isn't unquestioning, its senior officers understand that no one elected them.