“To make matters worse for Trump, there is little he can do to thwart the new investigation. Unlike the Mueller investigation, which Trump could end himself, the Cohen investigation in the Southern District would be extremely difficult for the White House to shut down. Trump could in principle fire the US attorney, a political appointee who serves at his pleasure, and appoint someone new with orders to end the Cohen inquiry. The civil servant prosecutors of the Southern District, however, cannot be fired except for misconduct. The strong tradition of prosecutorial independence means that, even if ordered to stop their investigation by Trump or a new US attorney, they would very likely treat such direction as itself a criminal obstruction of justice and find a way to keep digging.”