On Tuesday, Homeland Security Secretary Jeh Johnson announced steps to enhance security at more than 9,500 U.S. federal buildings amid the ongoing threat of attacks from extremist groups. Johnson called for continued vigilance and “guarding against potential small-scale attacks by a lone offender,” an obvious reference to the shooting at Canada’s parliament building earlier this month.

“We are taking this action as a precautionary step, to safeguard U.S. government personnel and facilities, and the visitors to those facilities,” he said, also noting that “given world events, prudence dictates a heightened vigilance in the protection of U.S. government installations and our personnel.”

The Federal Protective Service is challenged to secure thousands of buildings where some 1.4 million people pass through each day. The new steps, which will be “continually re-evaluated,” highlight growing public concern over how ready the United States is to halt threats large and small—and in what way. The helter skelter nature of quarantine rules for airline passengers arriving from West Africa, for example, are a show of force, but many physicians, experts and even the President have argued that it is the wrong approach. Will this kind of tactic be used for travelers from other areas ravaged by some infectious disease?

Consider the misplaced sense of security that came to a cataclysmic end in April 1995, when Timothy McVeigh detonated a bomb in front of the Alfred P. Murrah Federal Building, killing 168 (many of them children) and injuring more than 680 others. That led to temporary street closures around the White House, which were made permanent after the September 11 attacks. A small example of how threats can drive strategy. But how effective is it to surge resources based on limited knowledge of a threat? Will Johnson’s order actually yield safer federal buildings or is it yet another example of “security theater,” which is, for better or worse, a pillar of modern American homeland security.