The 10 Biggest Intelligence Leaks In U.S. History
The United States likes to keep a lot of secrets.
Published 5 months ago in Wow
The United States keeps a lot of secrets. Many of them we'll probably never know, but thanks to the efforts of some brave individuals, many classified documents have been brought to light over the years. This information often contains military plans, human rights abuses, or various opinions that people in power would rather keep to themselves.
These 10 intelligence leaks are among the biggest in US history, exposing all types of compromising communications and sensitive data. Don’t worry, you’re not going to go to jail for reading this list. But I’d watch your back.
1
Edward Snowden
In 2013, Edward Snowden leaked a set of intelligence documents revealing the inner workings of the secretive NSA, proving that the government was covertly and illegally collecting the phone data of US citizens. This was one of the largest leaks in US history. Snowden had to flee the United States and now lives in exile in Russia.
2
Reality Winner
Reality Winner, a former NSA translator, was arrested and charged in 2017 for sharing a classified report to a news website. This report detailed efforts by Russia to interfere in the 2016 presidential vote by using a phishing scheme. Winner believed that the public had a right to know about Russia’s attempts to meddle with voting. She spent four years in prison and was released in 2021. Her story was made into a movie starring Sydney Sweeney in 2023.
3
Pentagon Papers
In 1971, an analyst at the RAND Corporation named Daniel Ellsberg leaked a US military report about the Vietnam War. This report revealed that the government had been hiding a lot from the public, with presidents repeatedly increasing the scale of the war while simultaneously knowing the conflict was probably unwinnable. It also uncovered many covert operations. Ellsberg was charged with espionage, but the charges were dismissed.
4
Chelsea Manning
In 2010, Chelsea Manning, who was a US Army analyst and soldier at the time, began sharing thousands of top secret intelligence documents with Wikileaks, an organization run by Julian Assange. Many of these were made public, containing information about wars in Iraq and Afghanistan and various diplomatic communications. Manning was sentenced to 35 years in prison but her sentence was commuted after she had served seven years.
5
Robert Hanssen
Robert Hanssen joined the FBI as a special agent in 1976. Unbeknownst to the US, he was a Russian asset, spying on the government for Soviet and Russian intelligence throughout his 25-year tenure in the Bureau. He sold thousands of pieces of classified information for millions of dollars in cash and diamonds. He was caught by law enforcement in 2000, just on the verge of retirement. Hanssen is now serving 15 consecutive life sentences without parole.
6
Jack Teixeira
In April 2023, a 21-year old Massachusetts Air National Guard intelligence employee named Jack Teixeira leaked highly sensitive documents onto the internet by posting them on a Discord chat room dedicated to playing Minecraft and other video games. These documents had details on Ukraine, South Korea, and other US allies. Teixeira was sentenced to 15 years in prison.
7
The Hutchinson Letters Affair
Taking a trip back in time, another intelligence leak happened before the US was even the US. In 1772, Benjamin Franklin received an anonymous package that contained leaked correspondences between Massachusetts Governor Thomas Hutchinson, Lieutenant Governor Andrew Oliver, and officials of the British military. These letters showed the governors’ sympathies lay with the British. Samuel Adams published the letters in the paper, and angry Bostonians called for the removal of Hutchinson and Oliver.
8
Yemen War Plan Leak
Very recently, in March 2025, officials from the current administration accidentally added Jeffrey Goldberg, the editor-in-chief of the Atlantic, to a private group chat. This gave Goldberg live access to classified military plans and documents detailing strategies, weapon shipments, and covert operations against the Houthi militia in Yemen. Goldberg seized the opportunity and published the information publicly.
9
Vault 7 Leak
Vault 7 is a series of classified documents published by WikiLeaks since 2017 that details the CIA’s cyber warfare and electronic surveillance practices. The files contain information on the CIA’s capabilities to compromise almost any piece of consumer technology, including cars, TVs, web browsers, and most smartphones. The Department of Justice called it “one of the most brazen and damaging acts of espionage in American history.”
10
The Antietam Leak
In 1862, just before the Battle of Antietam– the bloodiest battle of the Civil War– Union soldiers discovered Confederate General Robert E. Lee’s battle plans in a package of cigars. This intelligence gave the Union army a crucial advantage, and marked a turning point in the war. If it weren’t for Robert E. Lee’s smoking habits, we might not have the Emancipation Proclamation.
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