Pentagon brass, already put on a spending and manpower diet by President Obama, are approaching the potential for many more years of cuts by determining how to stay ready for action with force levels and equipment that are just good enough to get by with.

Commandant James Amos, predicting that the austerity campaign could last another eight years as the Pentagon withdraws from Iraq and Afghanistan, said he is telling marine leaders to plan for using older equipment and reducing capacity and capabilities.

"You can talk to everyone of my generals and my senior colonels, they have heard this pitch from me, we are in this period of austerity and damn it you had better figure out what's good enough because we can't afford everything," Amos told a military strategy forum Thursday hosted by the Center for Strategic and International Studies.

Amos said the pitch being made in all the services is similar: "What is it our nation should do in global power?" But, he warned, "I don't think it should be begin with, 'What can we afford?'"

Still, he said the Pentagon is bracing for more cuts as the president and Congress negotiate the looming "fiscal cliff."

Once the role of the military is settled, the budget and strategy issue will be put before the generals. "Now how do we do it?" said Amos, adding, "then we ask ourselves a question. 'What's good enough? What is good enough to be able to do that?'"

Amos, who is cutting his troop level from a war high of 202,000 to 182,000, said he is confident that the marines will be able to do their job without losing skills picked up in Iraq and Afghanistan. "We are the world's only superpower," he said. "You don't know when you are going to have to force your will on people."

But he openly expressed concern that cuts will impact "capability" and "capacity" because at his current budget level "we're essentially just muscle."