The word "breach" is thrown around like a water molecule in a bubble these days, but to understand how the supposedly impenetrable White House could be "crashed" (another popular word -- one conjures up Vince Vaughan) by members of the pseudo-celebrity class, it's important to take a few steps back.
First, let's dismiss the dismissers. The Secret Service, quite appropriately, is chagrined at the notion that President Obama was ever put in danger by a lapse in their procedures. But access to the White House is limited for a reason: before someone darkens the door at one of the perimeter checkpoints, he or she has been pre-cleared -- given a cursory background check -- by civilian USSS staffers who run a semi-automatic clearance and processing system called WAVES. I've seen top journalists turned away because they hadn't been cleared through WAVES; the Uniformed Division of the Service, which staffs the perimeter guardhouses, is trained to turn away even celebrities and recognizable names who aren't on the list. But I've seen WAVES procedure be circumvented if a West Wing staffer vouches for you at the last moment. Indeed, I've been cleared into the West Wing despite a staffer having forgotten to request a WAVES clearance for me.
At major events, the Uniformed Division officers are often overtaxed as they try to clear through dozens of people waiting on line. The Division is already understaffed. At big events, supervisors increase the size of the duty roster. Still, the West Front gate on the North Lawn -- the checkpoint "crashed" in this instance -- has exactly one magnetometer, which means that people are forced to wait in line, which means that people get anxious and frustrated, which means that the officers get anxious and frustrated. Occasionally, a supervisor or an extra officer is dispatched to help speed people through -- one person checks photo IDs against the lists, isolates the cleared folks outside the gate, and then directs them through the line.
The notion, put forth by Rep. Peter King (R-NY), that uncleared visitors could sneak anthrax into the White House is absurd. Though the Secret Service doesn't talk about their methods, they employ extremely sophisticated chemical, biological and nuclear sensors around the White House perimeter. They regularly "red cell" these senors -- that is -- they try to sneak stuff through -- and then recalibrate as necessary. It's essentially not possible for anyone to bring a highly toxic substance into the White House. At events outside the White House, it might be easier -- I presume the Secret Service has clandestine senors at work, too -- but I'm not as certain.
King, a frequent critic of the Service, also worried that uncleared visitors could pick up a knife on the dinner table and try to cut the president. That's true -- but it assumes that the visitor somehow makes it past the extremely suspicious eyes of Joe Clancy and the rest of the shift agents who train for the day when a mentally disturbed person or a stealth assassin pulls a knife or a stiletto poison dart on a protectee.
In all likelihood, this incident will enflame tensions between the Uniform Division officers and special agents on protection details, the formers' performance bearing directly on the anxiety of the latters'. And in a context where the White House and the Secret Service are sensitive to the notion (not 100% correct) that Obama receives more serious threats than his predecessors, the media can exaggerate the danger of routine, human errors like this one. Even though the White House staff has insisted that the Service was solely responsible for clearing in visitors, we just don't know whether any White House or State Department protocol staffer influenced the decision-making of the Uniformed Division officer who cleared in the celebrity couple. We don't know whether, in the confusion of the large crowds, they were accidentally segregated into a "cleared" space before they went through the mags. The Service's Office of Professional Responsibility is investigating.