The origins of Watergate reach back before the June 1972 burglary. In 1971, after the Pentagon Papers were leaked, the Nixon White House created a special investigations unit commonly known as the White House Plumbers. Its purpose was to stop leaks of classified information and investigate those considered political or security threats.
The unit became associated with covert activity outside normal law-enforcement channels. E. Howard Hunt and G. Gordon Liddy were among the figures linked with these operations. The group’s activities included the break-in at the office of Daniel Ellsberg’s psychiatrist, an episode that later became important evidence of abuses of presidential power.
The Plumbers did not by themselves constitute the entire Watergate operation, but they created personnel, methods and a culture of political intelligence that overlapped with later campaign activity. National Archives material treats their formation after the Pentagon Papers leak as an important starting point for the wider Watergate story.