The cellphones of dead people were still ringing inside the Pulse nightclub on June 12 when Cathy Lanier, chief of the Metropolitan Police Department in Washington, D.C., got a message from her counterparts in Orlando, Florida. First reports were that a terrorist had carried out "the worst mass murder in American history" there.

A famously hands-on and nocturnal leader, Lanier started punching numbers on her cellphone. One call went to the Joint Terrorism Task Force, the FBI-led body that gathers intelligence on threats. Another went to the city's homeland security ops center. A text message came in from D.C.'s mayor, Muriel Bowser, asking for information. Lanier then set up a conference call with her senior commanders, who were already out in force because of the revelers in town for the city's annual gay pride weekend. Extra resources were deployed into the nightclub district and venues connected to the day's march, expected to draw over 250,000 people. As the sun lit up the Washington Monument, D.C.'s Homeland Security and Emergency Management Agency, a 24/7 nerve ganglion of blinking phones, 911 operators, intelligence analysts, computers monitors with incident reports, and banks of TV screens with camera views of the city's major avenues and bridges, was pulling in data from all over the region. Metro subway managers, struggling with repairs that shut down some lines, were on alert. Everyone from hospital emergency rooms to the power system and business association had been given notice that something bad was going down 850 miles south and could be coming their way.

"What you would expect," Lanier tells Newsweek of her long morning of putting her many pieces in place. Business as usual for the city's most high-profile, and perhaps popular, official, an instantly recognizable, 6-foot blonde who's often seen behind the wheel of her own cruiser in the city's poorest wards. If the history of terrorism since 9/11 has been a sad litany of "lessons learned," Lanier, who joined the force as a foot patrolwoman in 1990 and quickly rose through the ranks to head its homeland security and counterterrorism division before becoming chief in 2007, is determined to be ready for any eventuality.

Nightclub shooters, like Omar Mateen? Check. Bombers, as in Brussels last year? Check. Anthrax? Check. Nuclear, chemical or biological weapons? Check, check, check.

Unfortunately for Lanier, the recent attacks in Orlando, Brussels, and Paris show that you can plan and train until your budget runs dry, and still you rarely stop a determined attacker. "Lone wolves" come out of nowhere. The urban guerrillas of the Islamic State group, or ISIS, use encrypted cellphones. Meanwhile, Lanier knows her city is not just a top-tier target but the greatest unclaimed prize for terrorists. It's the thriving capital of their arch-villain, home to the president who has vowed to destroy them, the Congress that funds the wars against them, the Pentagon that carries out the president's orders and the Supreme Court that helps keep their brethren in Guantánamo.

"Suffice it to say, the capital remains a target," Rep. Michael McCaul (R-Texas), chairman of the House Homeland Security Committee, tells Newsweek. "They like to return to targets they missed" the first time around, like the World Trade Center, whose garage was merely wobbled by a truck bomb in 1993. "We've stopped several plots against the Capitol," he adds. One case involved pipe bombs and AK-47s; another had drones with explosives. There have been other, more recent plots, he says, but "I'd rather not get into that."

"God willing," a fighter proclaimed in a typical ISIS video from November 2015, "as we struck France in the center of its abode in Paris, then we swear that we will strike…Washington."

One day, Lanier knows, they will come. And despite all her tireless training, surveillance, and planning, she knows she can't stop them all.

Read the rest of this story at Newsweek.

Newsweek Magazine subscribers enjoy print and digital subscriptions starting at $14. You can follow Newsweek on Twitter and Facebook for breaking news and analysis daily.