WASHINGTON (AP) - A new book says that as President Barack Obama considered adding as many as 40,000 U.S. forces to a backsliding war in Afghanistan in 2009, Vice President Joe Biden warned him that the military rationale for doing so was flawed.

The book also quotes a U.S. official as saying that Obama purposely did not read a grim CIA assessment that found little benefit from the 30,000 "surge" forces Obama eventually approved.

The book says the White House wanted to stick to its plan to begin withdrawing those forces in July 2011, after what it argued was a successful but temporary expansion of the war.

A copy of "Little America: The War Within the War for Afghanistan" was obtained by The Associated Press. It will be released Tuesday.

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