SCOTT DETROW, HOST:
After the 9/11 attacks 20 years ago, security officials sprang into action in Washington, D.C., to protect government buildings from possible additional attacks by terrorists. The measures changed how Americans access their government, but new threats show yesterday's security still may not be enough. NPR's Brian Naylor reports.
BRIAN NAYLOR, BYLINE: In the weeks and months after 9/11, Washington became a sort of security garden. Planters, cement bollards and barriers suddenly sprouted from the sidewalk, like here in front of the EPA. It became what University of Virginia architecture professor Elizabeth Meyer calls a landscape of fear.
ELIZABETH MEYER: What's happened to the public landscape of Washington is more than the architecture of bollards and the immediate choreography of security and risk adjacent to public buildings. It's the total change of flow and accessibility that everyday citizens used to have to seats of power.
NAYLOR: Meyer wistfully remembers bringing classes up from Charlottesville and sitting on the Capitol steps overlooking the National Mall.
MEYER: To be sitting with 100 people on the steps of the West Front of the Capitol, no security anywhere - and, in fact, while at that time there was a little bit more locking of doors, you could still walk in - just walk into the building, right?
NAYLOR: Those days have long-since passed. Security really began to harden in Washington after the 1995 Oklahoma City truck bombing, which destroyed a federal building there, killing 168 people. Soon after that, the stretch of Pennsylvania Avenue that runs in front of the White House was closed to traffic. And after 9/11, Meyer says, security officials went into hyperdrive. They installed metal detectors inside buildings and outside forever altered Washington's appearance.
MEYER: Our conception of the public space of the city is dramatically different, and our sense of connection to the federal staff who support democracy is much more isolated and removed.
NAYLOR: And that's a problem, says Ed Feiner, who was chief architect of the General Services Administration, which oversees federal buildings.
ED FEINER: We should never lose sight that the citizens of this country - they own the government. And you can't separate that government from the people.
NAYLOR: In the years since 9/11, there's been a gradual adaptation to the security environment. Landscape architects have designed berms, like at the Washington Monument, that serve as vehicle barriers but unobtrusively blend in with the surroundings.
FEINER: There is a balance.
NAYLOR: Again, Ed Feiner.
FEINER: And if you balance too hard on separating the government from their people - the people - then the terrorists have won because that's exactly what they want.
NAYLOR: And neither vehicle barriers nor a newly constructed visitor screening center stopped a pro-Trump mob from storming the Capitol on January 6. Former Secret Service agent Jonathan Wackrow, now a security consultant, says the response after 9/11 to build barriers and bollards was appropriate at the time. But he says security needs to be adaptable.
JONATHAN WACKROW: I think that the way we need to think about this is first understanding that threats never remain at rest. They're dynamic. They're unpredictable. And they're constantly evolving.
NAYLOR: Some of the latest threats to the government come from hackers. Yet at the same time, officials must also prepare for an upcoming rally near the capital of supporters of those arrested January 6. A person familiar with the discussions tells NPR that Capitol Police are planning to reinstall a fence around the building to protect against that threat.
Brian Naylor, NPR News. Transcript provided by NPR, Copyright NPR.