He's done protecting. Secret Service director Mark Sullivan announced Friday he'll be retiring from his post, effective Feb. 23. It's unclear whether the decision has anything to do with last year's secret service prostitution scandal during President Obama's trip to Colombia. Sullivan served in the agency for nearly three decades and was head of the Secret Service for seven years. "From securing large events such as presidential inaugurations to safeguarding our financial system, the men and women of the agency perform their mission with professionalism and dedication," President Obama said in a statement. "That is a testament to Mark and his steadfast leadership, which will be missed."