Why Julia Pierson, first woman head of US Secret Service, felt she had to quit
Having presided over a series of blunders as head of the US presidential protection unit, Julie Pierson lost confidence of her boss and Congress
But last week it emerged that brief ride had severely compromised the US president's safety as the guard standing next to him had not only a gun, but a string of criminal convictions - and what is more, the woman in charge of protecting him failed to tell him.
The revelation was the final straw for Obama - who had hand-picked Julia Pierson for the job - and sparked the beginning of an embarrassing end for the nation's first woman to head up the Secret Service after just 18 short months. On Wednesday, she finally resigned.
Pierson was given the top job in March last year tasked with one key objective: keeping the president, his wife and two daughters safe. Described as "eminently qualified" by the president, she vowed to transform the culture of the service marred by a string of scandals.
Just two weeks ago the 55-year-old was confident she had begun to make changes, putting some of the agency's most troubling security lapses behind her.
In an interview in August, the director boasted to journalists: "It's been a year of challenges and success. We are doing great."