The 2005 base-realignment effort, which cost the government rather than adding savings, should not be used as a guide, he asserts. Rather, two rounds of base closures in the 1990s eventually provided an average annual cost savings of $2-3 billion per year, Hale adds.

The president, now past his final election, could push for a base closure round. And Congress has a year to put it forward that is not consumed with a presidential election. But, a lobbyist points out, midterm congressional elections are just around the corner.

The outlines of investment cuts are taking shape, says a Senate aide. The Army is transforming costly heavy brigades into lighter ones and aiming for an earlier down-select of one contractor for the Ground Combat Vehicle—both moves that could save dollars.

Once the initial block-buy of Littoral Combat Ships is completed in 2015, the Navy could opt to truncate the purchase of more vessels or down-select to one contractor in favor of purchasing Virginia-class submarines or Aegis ships, the aide says.

Plenty of think tanks have offered up their ideas about how the Pentagon can extract dollars. Michael O'Hanlon of the Brookings Institution suggests a number of options, including halving the purchase of F-35 Joint Strike Fighters and scrapping the replacement program of Ohio-class submarines while continuing to make the older version. Both ideas would encounter significant resistance among lawmakers.

On top of all of these potential outcomes, the situation within the Pentagon is compounded by the fact Defense Secretary Leon Panetta is retiring and the approval of former Sen. Chuck Hagel (R-Neb.) as successor is still not certain.

Hagel, whose confirmation is under fire in part because he bucked the Republican Party's position on Iraq war policy, earned a reputation for backbone. “He's willing to say 'no' and alienate people,” says John Isaacs, executive director of the Council for a Livable World.