“Law enforcement is not automatic. It isn’t blind. One of the greatest difficulties of the position of prosecutor is that he must pick his cases, because no prosecutor can even investigate all of the cases in which he receives complaints,” Attorney General Robert Jackson told a gathering of U.S. attorneys in 1940. “If the prosecutor is obliged to choose his cases, it follows that he can choose his defendants. Therein is the most dangerous power of the prosecutor: that he will pick people that he thinks he should get, rather than pick cases that need to be prosecuted.”