During the Bush and Obama Administrations, the Nation has witnessed major separation of powers controversies. In the war powers arena, for example, there has been great debate about what the President may do unilaterally, and what he can do only with congressional authorization, whether it be with respect to drones, surveillance, interrogation, military detention, or military commission trials. In the domestic arena, the Senate confirmation process, especially for confirming judges, has been the source of continuous friction. The Executive Branch and Congress also have been locked in contentious debates over the scope of the President's power to decline to follow or enforce laws passed by Congress, including the scope of the President's prosecutorial discretion. And the role of independent agencies, such as the FCC and the SEC, likewise has continued to prompt much controversy. Brett Kavanaugh was a White House lawyer and senior White House staffer from 2001 to 2006 during the Bush Administration. Since 2006, he has been a judge on the U.S. Court of Appeals for the D.C. Circuit, which adjudicates many high-profile separation of powers cases. He will discuss the enduring importance of our Constitution's separation of powers, his experiences amidst these controversies, and what lessons we can learn for the future.