In a recent article in The National Interest and a public appearance at the Nixon Center, Perle has tried to sell the story that neither he nor his fellow neoconservatives had any significant influence on the foreign policy of the Bush administration, and especially the decision to invade Iraq. Specifically, he denounces the supposedly "false claim that the decision to remove Saddam, and Bush policies generally, were made or significantly influenced by a few neoconservative 'ideologues.'" He suggests that no one has ever documented this claim, either conveniently ignoring the many books and articles that did exactly that, or misrepresenting what these works actually say.
Rather, numerous accounts have documented that they had been openly pushing for war since 1998 and they continued to do so after 9/11. As neoconservative pundit Robert Kagan later admitted, he and his fellow neoconservatives were successful in part because they had a "ready-made approach to the world" that seemed to provide an answer to the challenges the U.S. faced after 9/11.
The bottom line is simple: Richard Perle is lying.