Senate officials moved operations to Fort McNair on Friday in a complex exercise designed to make sure they could relocate lawmakers and staff to a fortified location in the event terrorists struck at Congress and rendered Capitol Hill uninhabitable.

Several hundred staffers participated in the daylong drill, which involved transporting equipment and aides from Capitol Hill to a building on the Washington, D.C., Army base that had been outfitted with 100 seats for Senators. To add a detail of reality to the proceedings, Walter Oleszek, a Congressional Research Service veteran who is an expert in legislative procedure, presided over a mock session.

“We are making sure the Senate can endure and that it is able to fill its constitutional duties,” said Senate Sergeant-at-Arms Bill Pickle. “This exercise we executed Friday is just one of many we are going to continue to do in the future.”

Pickle would not confirm the location of the Senate’s alternative site, but several individuals involved in the exercise said it was Fort McNair, the headquarters of the U.S. Army Military District of Washington. Participants, speaking on the condition of anonymity, described the venue as a small theater-style setting with limited space for staff other than the personnel essential to running the chamber. In the event the Senate needed to move to Fort McNair, the room has been wired for cameras and sound to allow the proceedings to be broadcast over the radio and television airwaves.

As evidenced by last night’s State of the Union address, security remains high on Capitol Hill — a reminder of the Sept. 11, 2001, attacks carried out by terrorists who hijacked airplanes and slammed two into the World Trade Center in New York City and another into the Pentagon, across the Potomac River from the Capitol. A fourth plane, which many believe was headed to the Capitol, crashed in a Pennsylvania field.

Pickle acknowledged the Capitol is a target and noted that is why officials are always on “high alert.”

“The Capitol remains the number one target of certain terrorist groups,” Pickle said. “We know this from a variety of sources, and based on that intelligence we are doing what we can to make sure that the Capitol, the Members and employees are safe.”

For security reasons, Pickle said he did not want to name the groups. Fort McNair is just one of many locations the Senate has identified as an alternative site to relocate the legislative body should a national crisis require so. On Capitol Hill, Room 216 in the Hart Senate Office Building — a large space often used for high-profile committee hearings — would be the first option to move Senate operations in the event of a smaller-scale emergency, sources said. Pickle would not name any of the locations either on or off Capitol Hill, but he did acknowledge that officials have identified several places throughout the country to reconstitute the Senate outside the nation’s capital.

“I think it is fair to say we are looking at sites that would allow us, if the worst-case scenario happened, to meet in a place other than Washington, D.C., that would have not only the facilities and accommodations but also the transportation as well as the ability to provide a secure environment,” Pickle said. “We have a number of places around the country that we are looking at.

“It is part of a normal continuity of government operation,” he added.

On a micro level, individual Senate offices continue to practice moving their offices off Capitol Hill should an attack force them to do so.

“We are still evacuating my office every quarter and we all gather out at a certain location off-campus and there is a little grumbling,” said Sen. Larry Craig (R-Idaho). “But that is the way you have to do it.”

The House did not participate in last week’s drill, but it conducts similar reconstitution planning and drills.

Prior to the terrorist attacks, Congress did not have a coordinated plan in place that fully addressed the reconstitution issue. Much has changed in two and a half years. Congressional offices have since been outfitted with emergency radios to alert staffers to evacuate the building; pop-up barriers have been installed on the streets leading to the Capitol; and police officers walk the Capitol grounds with high-powered weapons slung across their shoulders. Security is now on everybody’s minds.

“Before 9/11 we never thought about it,” said Sen. John Breaux (D-La.). “But since then, I think people are more prepared.”

“I think a great deal of thought has gone into how we might do that and we are far better prepared today then we were on 9/11,” added Minority Leader Tom Daschle (D-S.D.) of the possible need to move the Senate to another location.

Pickle said the Senate could move to another location off Capitol Hill within a few hours. The ultimate decision to reconstitute off-campus would be made by the Senate leadership, he said.

Still, Pickle said he has the highest confidence in Capitol Hill’s ability to withstand an attack.

“There is nobody better in the country I think at this point in emergency preparedness and emergency planning than the House Sergeant-at-Arms, Senate Sergeant-at-Arms and the Capitol Police,” he said. “I don’t think anybody is better.”