On 19 September Omar Gonzales jumped the fence of the home of the President of the United States armed with a knife.
He sprinted across the White House lawn towards the front door.
The plainclothes surveillance team whose job it is to detect fence jumpers and protect the most powerful man in the world didn't stop him.
The Secret Service officer in the North Lawn guardhouse did not stop him.
The attack dog did not stop him.
The Secret Service guard at the front door did not stop him.
The SWAT team at the front door did not stop him.
The alarm box designed to alert the building to an intruder had been muted.
The intruder was finally tackled inside the East Room.
Seven successive failures in decision making.
16 breaches of White House security in the last five years. Six this year. 'Hundreds' have approached the perimeter and made verbal threats.
The fear of being wrong is understandably a major influence on our decision making.
As someone wrote - we tend to compare our bloopers with everyone else's highlight reel.
Yet if the United States Secret Service - with a budget of $1.8 billion and the job of protecting the most powerful man in the world - can fail in each of seven layers of defence - we can feel a little better about getting it wrong.