by David Vose

We learned recently about how, in August 2014 Omar Gonzalez, a US war veteran who had been wounded in Iraq and psychologically affected by his experience3 , had managed to enter the White House with a knife evading all security.

We also heard how, back in July, Mr Gonzales had been stopped in his car after driving recklessly in Virginia, a state that shares a border with Washington DC, and found to have in his truck (in which he slept) 11 weapons including a sawn-off shotgun, assault rifles, knives, ammunition … and a map marking out the White House. Virginia State police informed the Secret Service. He’d also been detained previously walking along the south fence of the White House carrying a hatchet … but apparently not arrested.

Mr Gonzales, a man with a limp, managed to climb the White House security fence, cross the lawn, go through the main entrance of the White House, cross the hall and into the East Room.

I used to work a great deal in DC and usually stayed at the Willard Hotel, one block from the White House. I’d often take a walk in the evening and pass by the White House. It impressed me how close people were allowed to get but, probably just like you, I imagined that if anyone attempted to climb the fence their feet wouldn’t touch the grass before they were pinned down by dogs and huge men with a dozen weapons pointed at them.

Really good security (and other risk reduction) systems are based on multiple, independent layers. To get through the security…