Bob Graham is the highest elected official that has challenged the government's narrative on 9/11. He was a US senator, the Chairman of the Senate Intelligence Committee and he led the joint congressional investigation into 9/11.
In these interviews, he indicates that there are reasons to believe that Bush administration had foreknowledge of the 9/11 attacks. These statements came long before the "28 pages", which removed any doubt that there was a cover-up after the fact and provided more evidence that Bush and his terrorist friends organized the whole thing.
https://www.youtube.com/watch?v=DRNti8P_o-I