Harrison laid some blame at the feet of the Pentagon and, indirectly, the White House, which chose not to plan ahead for sequestration and did not prepare a fallback 2014 budget reflecting the spending caps.

Defense officials insisted for months that OMB had not instructed them to plan for sequestration — but they made a political gamble as well, worrying that if they showed they could absorb the roughly $500 billion in restrictions over the coming decade, that might make the cuts more likely to take effect.

The bottom line, Harrison argued, is that the Pentagon must seize as much control as it can of costs and overhead on the assumption that Congress will not be of much help in the near term. That means defense officials must offer to cut their own workforces, do their own consolidation and generally demonstrate they are willing to make their own tough choices, he said.

If the Pentagon and Congress cannot get the present trends in the defense budget under control, most of the money the department gets will go to pay for personnel, benefits, health care and only some operations and maintenance, Harrison warned. DoD’s share of the cost of a single uniformed service member has grown from about $70,000 per year in 2001 to $110,000 this year, he said. Personnel costs now represent about 36 percent of the defense budget, a figure that will grow to 46 percent by fiscal year 2021, when sequestration ends.

A total of 86 percent of the Pentagon’s budget will go to its personnel and operations and maintenance accounts in fiscal 2021, Harrison said — leaving an ever-smaller share of the pie for research, development and acquisition. Although Harrison said he thinks Hagel understands the problem, citing his speech this week at National Defense University, Harrison said the true test will be whether the Pentagon and Congress can actually act.

“If you don’t start this now, you’re never going to get ahead of the curve,” he said.