Last week, a group of five former deputy defense secretaries — essentially the Pentagon’s chief operating officers — called for a “bottom up” review that reassesses the need for each major program and weapons system, saying this was an opportunity to accomplish cuts that have long been delayed, after a decade in which the American national security budget has nearly doubled.

In their more candid moments — almost always when speaking with a guarantee of anonymity — the Pentagon’s top civilian and military leaders acknowledge that the painful sequestration process may ultimately prove beneficial if it forces the Defense Department and Congress to reconsider the cost of cold-war-era systems that are still in inventory despite the many changes made to the military in the last 10 years.

“Sequester is an ugly experience, but it could grow up to be a budget discipline swan,” said Gordon Adams, a former senior budget official in the Clinton administration who is now at the Stimson Center, which studies defense issues. “It could provide the planning discipline the services and the building have been missing since 2001.”

The central challenge facing the Pentagon and the White House, Mr. Adams and several current senior officials said, is this: All the big, immediate budget benefits come from reducing the size of active-duty forces. By contrast, cutting new weapons systems and bases and reducing health care costs can save large amounts 5 to 10 years out, but it does little in the short term.

Mr. Obama took a step in that direction in 2011, when he rejected a Pentagon request for a permanent standing force of 100,000 or so troops for future “contingency operations” like those in Iraq and Afghanistan. “That’s not the way we are going to go,” he told his staff after the request was received.

The message quickly got back to the Pentagon that Mr. Obama had no interest in repeating the kind of lengthy interventions that have consumed more than $3 trillion since the attacks of Sept. 11, 2001.