Over the nearly 50 years since the Watergate hearings, congressional oversight committees have obtained information from the White House and other executive agencies on a wide variety of sensitive subjects such as the exercise of presidential constitutional authority, White House security, Department of Justice investigations, and interactions between the White House and top cabinet officials. This guide summarizes key precedents concerning executive branch document production and the congressional testimony of senior administration officials including White House chiefs of staff, White House counsels, and national security advisors. Additional precedents will be added to this page on a rolling basis.