But Gordon Adams, an American University professor who worked on defense spending at the White House budget office in the 1990s, said the cuts could help restore a sense of discipline at the Pentagon after a decade of rapid growth and two wars.

“They doubled the budgets and lost the capacity to set priorities and make hard choices,” Adams said. “If sequester sets in motion a recognition that budgets are coming down ... then it ... creates the incentive for greater discipline.”

Retired Admiral Gary Roughead, the former top U.S. Navy officer, and Kori Schake, a researcher at the Hoover Institution think tank, said in a recent policy paper that the all-volunteer military was a key driver of rising costs.

The Pentagon says nearly a quarter of President Barack Obama’s $613.9 billion defense budget for 2013 was for military personnel and another 12 percent for civilian employees. In all, Pentagon personnel costs amounted to about $220 billion.

Those costs have been rising quickly. Harrison said in a recent study that military pay and benefits grew by 46 percent per person between 2001 and 2011. If growth remains unchecked and budgets stay flat, personnel costs could consume the entire defense budget by 2039, he found.

“We have a guns-versus-butter tradeoff going on inside the defense budget, where the personnel accounts have grown at galloping paces,” Schake said.

Congress has been reluctant to take on the issue. Lawmakers have blocked Pentagon efforts to increase healthcare insurance fees and sometimes have approved pay raises higher than those proposed by the Defense Department.

“It’s a very emotional issue,” said Schake, who has taught security studies at West Point and the National Defense University. “It gets cast in terms that any changes to current compensation (is) breaking faith with our military forces.”