Defense officials repeated their plea to Congress on Thursday for another base closing round, and once again received partial empathy for their cost concerns but no real path forward on the controversial proposal.

The Pentagon's fiscal 2017 budget request marks the fifth consecutive year military leaders have requested a new base closing round, arguing the services' stateside footprints are too large given drawdowns in troops and equipment over the last decade.

Pete Potocheney, acting assistant secretary of defense for installations, estimated a base closing round in 2019 will save about $2 billion annually, and promised the process would be "efficiency focused" and designed to cut military costs.

"We are in a tough budget situation," he said. "We need to make tough choices. And we need a BRAC."

But lawmakers have strongly resisted the proposal in recent years, typically pointing to the questionable savings and chaotic implementation of the 2005 base realignment and closure round. That "force-shaping" process trimmed only about 3 percent of the military's U.S. infrastructure, far below what earlier rounds had done.

Last year, Congress conceded to allow Pentagon officials to conduct a defensewide study of excess infrastructure capacity, without promising those findings would directly lead to a new base closing round.

Potocheney said that work is underway, but he expects to find about 20 percent excess capacity, based on studies from the department in the early 2000s.

Miranda Ballentine, Air Force assistant secretary for installations, said her service's unused space likely tops 30 percent.

"We simply cannot afford to maintain our current infrastructure footprint," she told lawmakers. "Sustaining and maintaining extra infrastructure strains our limited funds by forcing us to spread them even further."

She and officials from the other services argued the next round could be done without jeopardizing the military's ability to boost end strength in the case of a future war, and could provide financial relief in the near future.

Lawmakers supported that concept — Rep. Jeff Fortenberry, R-Neb., begged witnesses to call it a "military infrastructure savings commission" instead of a base closing round — but did not offer any promises to adopt the proposal this budget cycle.

Potocheney said officials are finding ways to close some buildings and runways to save on maintenance costs, but that base closings will be needed to achieve substantial savings.

Leo Shane III covers Congress, Veterans Affairs and the White House for Military Times. He can be reached at lshane@militarytimes.com.