WASHINGTON ‚?? The White House says President Barack Obama has picked top national security aide Denis McDonough as his next chief of staff. Obama will announce McDonough‚??s appointment from the White House Friday. McDonough will take over the key West Wing role from Jack Lew, Obama‚??s nominee for Treasury secretary. McDonough has long advised Obama on foreign policy, most recently serving as his deputy national security adviser. During his four years at the White House, McDonough has emerged as one of the president‚??s most trusted advisers.