Operation Northwoods: Documents declassified in the 1990s revealed that in the early 1960s, the U.S. Department of Defense proposed plans to commit acts of terrorism on U.S. soil to justify military intervention in Cuba
MK-Ultra: The CIA's MK-Ultra program, which ran from the early 1950s until the 1970s, involved experiments on humans to identify and develop drugs and procedures to be used in interrogations and torture.
Tuskegee Syphilis Study: From 1932 to 1972, the U.S. Public Health Service conducted a study on the progression of untreated syphilis in African American men without their informed consent
Watergate Scandal: Initially dismissed by some as a conspiracy theory, the Watergate scandal involved a break-in at the Democratic National Committee headquarters
Iran-Contra Affair: In the 1980s, allegations that the U.S. government was secretly selling arms to Iran and using the proceeds to fund Contra rebels in Nicaragua were initially met with skepticism.
Operation Ajax: The CIA's involvement in the 1953 coup that overthrew Iran's democratically elected Prime Minister Mohammad Mossadegh was long suspected.
NSA Mass Surveillance: Edward Snowden's leaks in 2013 confirmed long-held suspicions that the National Security Agency (NSA) was conducting widespread surveillance on American citizens
COINTELPRO: The FBI's COINTELPRO program, aimed at surveilling, infiltrating, discrediting
Gulf of Tonkin Incident: Initially reported as an unprovoked attack by North Vietnamese boats on U.S. naval vessels, later evidence suggested that the Gulf of Tonkin incident
Operation Gladio: After the Cold War, evidence emerged of Operation Gladio, a secret NATO project that involved maintaining stay-behind armies in Europe to engage in sabotage