What did US intelligence know before the 9/11 attacks?

Twenty-five years after the September 11 attacks, the CIA has released a series of presidential briefing documents showing what United States leaders had been told about Osama bin Laden and al-Qaeda in the years before the plane hijackings that killed nearly 3,000 people.

CIA Director John Ratcliffe called the release of the documents “an act of exceptional transparency”. Thi...