Arlington County leads the hit parade on the Defense Department's base-closing list.

The Pentagon's proposed base closings, announced last month, would eliminate almost all of the department's leased office space in Arlington, according to an analysis prepared by Moody's Investors Service.

About 23,000 Defense employees would be moved out of the leased space in Rosslyn, in Crystal City, along Columbia Pike and in other locations. Their jobs would be shifted to area forts, such as Belvoir and Meade, and to places out of state, such as Redstone Arsenal in Alabama, Buckley Air Force Base in Colorado, Scott Air Force Base in Illinois and Fort Knox in Kentucky. Several thousand contractors also would find their work lives disrupted.

Rep. James P. Moran Jr. (D-Va.), who represents Arlington, said the initial feedback from Defense officials indicates that half to three-quarters of employees caught up in the base closings might balk at moving.

Some of the employees would face longer commutes, and others would have to decide whether to ask a spouse to give up a job, pull kids out of schools and move away from friends, Moran said.

The Pentagon recommendations, if approved, probably would create "a serious brain drain" at Defense agencies leaving Arlington, Moran said. "It just doesn't make sense to break down the synergy we have achieved in Northern Virginia between DOD agencies, the contract personnel and the other parts of the federal government that they work so closely with," he said.

In an attempt to learn what federal employees think about the Pentagon recommendations and to discuss Pentagon criteria for the use of leased space, Moran, Rep. Thomas M. Davis III (R-Va.) and Sen. John W. Warner (R-Va.) have scheduled a town hall meeting at noon Monday in the law school atrium at George Mason University in Arlington. (For details, call 202-225-4376.)

Davis said he is concerned that when the time comes to make a decision, Defense employees might opt out of the government rather than ask their families to move. "Smart people who are working for the government can easily find jobs in the private sector," Davis said.

Employees who have security clearances, in particular, are in demand. "It's like being a left-handed relief pitcher," Davis quipped.

Defense agencies support the Pentagon recommendations but acknowledge that they probably will face staffing disruptions if the proposed moves are not changed by the Base Realignment and Closure Commission, known as BRAC, or the president or Congress.

For example, the Defense Information Systems Agency and Joint Task Force-Global Network Operations would move out of buildings on Columbia Pike and in the Skyline complex and relocate to Fort Meade in Maryland. The two organizations have nearly 2,600 military and civilian personnel in the Washington area, and 75 percent of them live in Northern Virginia.

DISA officials estimate that they would lose at least 50 percent of their workforce because of the relocation. "This loss will have an impact on DISA's ability to meet mission requirements because of the time required to reconstitute the workforce," an agency spokesman said.

About 2,000 of the 3,600 Washington area employees and contractors for the Missile Defense Agency would move to Huntsville, Ala. Many work in 11 sites in Northern Virginia. David Altwegg, deputy director for business management at Missile Defense, said experiences with BRAC and other relocations indicate that 60 percent to 70 percent of the agency's staff "may decide they prefer to stay here in the Washington area or not go to Huntsville." But he said the agency believes it would be able to "manage through that," if necessary, and hire qualified replacements in the Huntsville region.

The Defense Advanced Research Projects Agency has about 240 employees and nearly 600 contractors in two buildings in Arlington's Virginia Square. They are supported by 900 contractors in the Ballston corridor. DARPA would move to Bethesda under the Pentagon plan.

The majority of DARPA employees come from industry, usually at some personal sacrifice, for three- to five-year projects. Program managers are critical to DARPA's success, and officials predict that recruitment will be difficult during the BRAC transition.

One agency official, in a BRAC presentation, said, "It may take years for DARPA to recover."