How 9/11 conspiracy theories moved into mainstream American politics

Conspiracy theories about the September 11 attacks have persisted and evolved in the decades since the event, increasingly finding audiences on social media platforms. What began with fringe theories has expanded across platforms like YouTube, where videos — some featuring well-known media figures — draw large numbers of views and recycle older suspicions about who was responsible for the attacks.

Analysts point to several factors that helped spread and normalize these narratives. The attacks were broadcast live around the world, creating a spectacle that many later scrutinised for apparent inconsistencies. That moment coincided with the rise of cable rolling news and the internet as primary information sources, which opened new spaces for debate and the rapid circulation of alternative explanations. The launch of video platforms in the years after 2001 provided fertile ground for films and clips — for example, the widely shared Loose Change — that advanced claims such as controlled demolition of the towers.

Political events and state actions also contributed to growing public scepticism. The US invasions of Afghanistan shortly after the attacks and of Iraq in 2003, the latter justified at the time by claims about weapons of mass destruction that were later disproven, eroded trust in official accounts. Experts cited in the reporting say that government falsehoods and perceived deception create fertile conditions for conspiracy beliefs, and that declining trust in media and institutions amplifies those effects.

Since around 2016, the character of conspiracy theories shifted as they became tools within mainstream political contests. The rise of 'post-truth' politics coincided with prominent politicians promoting or amplifying conspiratorial narratives — from birther claims about President Barack Obama to accusations of a 'deep state' — and movements such as QAnon and false claims about the 2020 election that contributed to the January 6, 2021, assault on the US Capitol. More recently, unsubstantiated allegations blaming Israel for involvement in 9/11 have resurfaced online, tapping into contemporary anger about the Gaza war and perceptions of foreign influence in US politics. Observers warn that far-right actors have increasingly used conspiracies to exploit grievances and broaden their political reach.