WASHINGTON — A former White House press secretary, Scott McClellan, blames President Bush and Vice President Cheney for efforts to mislead the public about the role of White House aides in leaking the identity of a CIA operative.

In an excerpt from his forthcoming book, Mr. McClellan recounts the 2003 news conference in which he told reporters that aides Karl Rove and I. Lewis “Scooter” Libby were “not involved” in the leak involving operative Valerie Plame.

“There was one problem. It was not true,” Mr. McClellan writes, according to a brief excerpt released yesterday. “I had unknowingly passed along false information. And five of the highest-ranking officials in the administration were involved in my doing so: Rove, Libby, the vice president, the president’s chief of staff and the president himself.”

Mr. Bush’s chief of staff at the time was Andrew Card.

The excerpt, posted on the Web site of publisher PublicAffairs, renews questions about what went on in the West Wing and how much Messrs. Bush and Cheney knew about the leak. For years, it was Mr. McClellan’s job to field —and often duck — those types of questions.

Now that he’s spurring them, answers are equally hard to come by. The current White House press secretary, Dana Perino, said it wasn’t clear what Mr. McClellan meant in the excerpt, and she had no immediate comment. Mr. McClellan turned down interview requests yesterday.

Ms. Plame maintains the White House quietly outed her to reporters. Ms. Plame and her husband, a former ambassador, Joseph Wilson, said the leak was retribution for his public criticism of the Iraq war. The accusation dogged the administration and made Ms. Plame a cause célèbre among many Democrats.

Mr. McClellan’s book, “What Happened,” isn’t due out until April.