The Pentagon’s proposal to begin a new round of base closings in the 2013 budget may be over before it started.

Sen. Claire McCaskill, (D-Mo.), chairman of the Senate Armed Services Readiness and Management Support subcommiteee, announced Wednesday that she will not allow the proposal for a Base Realignment and Closure Commission (BRAC) to move forward.

Sen. Claire McCaskill (D-Mo.) (J. Scott Applewhite/AP)

“I will not support the request for a BRAC process to be carried out in 2013,” McCaskill said during a hearing before her subcommittee on the Pentagon’s plan. McCaskill’s announcement effectively kills the proposal, at least for the time being.

A senior Pentagon official told panel that BRAC is a critical tool in the Defense Department’s efforts to cut costs.

“The math is straightforward,” Dorothy Robyn, deputy undersecretary of defense for installations and environment, told the subcommittee. “BRAC is the single most effective thing the department has ever done in terms of producing greater efficiency and savings.”

McCaskill, who faces reelection this year, expressed concern about the fate of bases in Missouri.

“The impact BRAC has on our communities around the country, such as those surrounding my home state bases Fort Leonard Wood and Whiteman Air Force Base, is extraordinary,” McCaskill said during the hearing.

“I will not support a process that is callous or casual, or one that is rushed before we fully comprehend whether the traumatic task is clearly in the best interests of the American taxpayer and our national security,” she added.

The proposal met a similarly dim reception at a hearing before the House Armed Services readiness subcommittee earlier this month.