At issue is whether the Pentagon can work quickly enough to prepare housing and training sites for the influx of troops, and whether the military has adequate air and sea lift to transport soldiers from the United States to foreign hot spots, members told the Senate Military Construction and Veterans Affairs Appropriations Subcommittee.
Meanwhile, a quick move -- mostly from Germany and the Korean peninsula -- might cost $20 billion or more and "adversely impact the services' ability to adequately fund modernization and transformation," commission Chairman Al Cornella told the panel.
Commissioners also warned that a hasty relocation might hinder recruitment and retention efforts, which have already faced serious challenges because of recurring deployments to Iraq and Afghanistan.
Subcommittee ranking member Dianne Feinstein, D-Calif., echoed many of the commissioners' fears and also noted that the Pentagon had not given enough thought to foreign policy, or to its "overreaching objectives," before preparing for the move.
Subcommittee Chairwoman Kay Bailey Hutchison, R-Texas, however, stated that delaying the move would postpone modernization efforts and the Army's transformation into a more nimble, brigade-based force.
In a "perfect world," military members and families would face no quality-of-life interruptions during the transfer back to the United States, but the impact of a delay on future plans would have even more devastating effects, she said.
Meanwhile, Pentagon officials contended that they have worked with the State Department on their overseas basing plan and have addressed foreign policy concerns with 20 nations.
Ryan Henry, the principal deputy undersecretary of Defense for policy, added that deploying troops from the United States for overseas contingencies, rather than directly from Europe or Asia, would not add any risk to operational and deployment plans.
"Uncertainty is part of the strategy landscape which we have had in the post-9/11 world," Henry said.
He added that the Pentagon will have a better idea of its strategic air- and sea-lift needs early next year, when it completes its massive Quadrennial Defense Review of military capabilities, force structure and plans.
Congress created the six-member overseas commission in 2004 to provide an objective, independent analysis of the Pentagon's global base posture plans. The commission submitted a preliminary report to Congress and the Defense Department in May, and will file its final report by Aug. 15.
Subcommittee members also voiced concerns about the overall cost of moving troops from overseas.
The Pentagon estimated that total costs could range from $9 billion to $12 billion, but a Government Accountability Office evaluation put the price tag at closer to $20 billion, much of which will come from the services' operations and maintenance spending accounts.
Defense officials told the commission that the total cost could come to $25 billion, Cornella said. And, while it is "logical to assume" that relocating troops to the United States might save some money in the long run, the savings might not amount to much because the military would have to replicate many of the facilities in Europe in the United States, he added.
"We just can't pretend we can do all of this with minimal-to-no cost," said Sen. Mary Landrieu, D-La.
If adequate funds are not set aside for the troop transfer and the Pentagon sticks to its current schedule, it "could drive unforeseen consequences," noted commission Vice Chairman Lewis Curtis.
But despite several concerns about the Pentagon's timetable, the effects on military quality of life and the services' lift capabilities, commissioners stressed that they largely agree with the premise for the Pentagon's global basing changes and its desire to relocate troops.