Sen. John W. Warner (R-Va.) yesterday challenged the legality of a Pentagon plan to move 23,000 military workers away from the close-in Northern Virginia suburbs by 2011 as part of a national defense streamlining proposal.

Warner, chairman of the Senate Armed Services Committee and co-author of the 1990 law guiding the military base closing process, added his influential voice to a chorus of Virginia and District leaders who testified against the impact of proposed changes at day-long hearings of the Base Closure Realignment Commission.

Warner said Defense officials illegally targeted for relocation military workers in leased office space and in the Missile Defense Agency, Defense Information Systems Agency and National Geospatial-Intelligence Agency.

"I know the law, and I know what Congress intended," said Warner, a former undersecretary of the Navy who has overseen from the Senate all five earlier base-closing rounds. "The goal to vacate leased office space was the guiding principle for many of these recommendations -- not military value, cost savings or any other legislated criteria. This is not permitted by law."

The District, Alexandria and Arlington County would be among the hardest-hit communities under a plan submitted May 13 by Defense Secretary Donald H. Rumsfeld. The plan would shutter defense facilities nationwide to save $49 billion over 20 years. It calls for the relocation of nearly 6,000 jobs from Walter Reed Army Medical Center in Washington to Bethesda and Fort Belvoir in southeastern Fairfax County.

Beyond the Capital Beltway, Maryland and Virginia would gain more than 20,000 jobs at suburban bases such as Belvoir, Fort Meade and Aberdeen Proving Ground, where the Pentagon says security is better and land is federally owned.

The hearings marked the first -- and likely last and best -- opportunity for local leaders to influence the nine-member commission, which is holding 19 such sessions across the country on its way to producing a final list of targeted bases Sept. 8. President Bush and Congress must accept or reject the list in its entirety.

Elected leaders nationwide have protested that the Pentagon did not follow its stated purpose of increasing "military value" in initiating the first round of base closings in 10 years. But District and Virginia speakers -- including Mayor Anthony A. Williams (D), Gov. Mark R. Warner (D) and five members of Congress -- brought new specificity to their case against Pentagon projections of cost savings and efficiency, saying emergency response in Washington and military research would suffer.

The "recommendation to vacate 8 million square feet of leased space in Northern Virginia is unnecessary for the security of our nation, inordinately expensive, inconsistent with . . . the law and inconsistent with the treatment of leased space in other areas of the country," Gov. Warner said.

Sen. Warner said the Pentagon should have asked Congress for specific authority to make base closing decisions based on the security of workers in leased buildings, whose closure affects about as many people as four major base closings in other states.

In a news conference later, the commission chairman, Anthony J. Principi, said the panel would consider a 36-page report and three legal briefs prepared by Sen. Warner's staff. But he added that past defense secretaries have been criticized for failing to protect troops, and he invoked "this terrible war on terror, and what we saw in London this morning."

"Do we want to establish a double standard, if we don't condone these efforts to establish the same force protection for our civilian workers, federal workers and our scientists in this area?" Principi said.

The Pentagon contends that putting workers in government-owned space will be cheaper in the long run and that the leased buildings in Northern Virginia fail a new security rule requiring structures to be set back 82 feet from traffic to guard against truck bombs.

Virginia officials say the Pentagon understated the costs of new construction, that urban buildings cannot meet the setback requirement and that the Pentagon and other high-security government agencies are not fleeing the capital.

In other testimony, Sen. George Allen (R-Va.) and military experts warned that the moves would erect barriers between researchers who are now concentrated in Arlington at the National Science Foundation and at the Defense Advanced Research Projects Agency and other military research agencies.

Arlington County Board Chairman Jay Fisette (D) asked the commission to consider moving 2,000 workers in those agencies to one of two Arlington sites that can be developed into secure leased space.

Reps. James P. Moran Jr. (D-Va.) and Thomas M. Davis III (R-Va.) said the Pentagon had unfairly targeted Northern Virginia and was setting itself up to fail.

Moran said Pentagon officials arbitrarily penalized local leased facilities 67 points out of 100 on ratings that are supposed to take into account factors on which the region would score highly, such as access to airports, availability of educated workers and quality of communications infrastructure.

Davis warned that three-fourths of skilled defense workers may simply quit instead of moving, given a local unemployment rate of 2 percent, a huge shortage of private-sector workers with security clearances and a national backlog of people seeking clearances now estimated at 329,000 people.

Earlier, on Capitol Hill, Williams, Del. Eleanor Holmes Norton (D-D.C.) and other District officials said the Pentagon understated the construction, environmental cleanup and historic preservation costs of moving Walter Reed.

Norton said Walter Reed, which has treated 4,000 wounded soldiers returning from Afghanistan and Iraq, serves a homeland security role in the city. "The closure of Walter Reed would . . . cripple the emergency response capabilities of our nation's capital in the event of a major disaster," she said.

Sens. George Allen and John Warner and Gov. Mark Warner, with bandaged hand, are sworn in before testifying against a plan to move 23,000 workers from close-in Northern Virginia suburbs. D.C. officials oppose moving 6,000 jobs from Walter Reed Army Medical Center.