At the age of 92, whistleblower Daniel Ellsberg passed away after revealing the extent of US involvement in the Vietnam War.
According to his family, he passed away from pancreatic cancer at his home in Kensington, California.
The former US military analyst was dubbed "the most dangerous man in America" as a result of the 1971 Pentagon Papers leak.
As the Nixon administration attempted to prevent publication in the New York Times, a Supreme Court case was eventually started.
However, accusations of espionage against Ellsberg were ultimately dropped.
Ellsberg vehemently opposed military interventions and governmental overreach for many years.
His opposition became more pronounced in the 1960s, when he provided the White House with nuclear strategy counsel and Department of Defense assessments of the Vietnam War.
Ellsberg's conscience was troubled by what he discovered during that time. If the general public knew, he reasoned, political pressure to end the war might become unstoppable.
This justification led to the disclosure of the Pentagon Papers.