Rumsfeld: Lack of Troops to Iraq Might Have Been Huge Mistake

Former Defense Secretary Donald Rumsfeld launches a vigorous defense of the Iraq war in his new memoir, “Known and Unknown.” But during his first TV interview since 2006, set to air on ABC’s “World News Tonight” Monday, former President George W. Bush’s aide acknowledges to Diane Sawyer that “it's possible" not sending more troops to Iraq early on constitutes the biggest mistake of the war.

Former Defense Secretary Donald Rumsfeld

"In a war, many things cost lives," Rumsfeld says. When Sawyer noted Bush has written that cutting troop levels in Iraq was "the most important failure in the execution of the war," Rumsfeld called that assessment "interesting."

"I don't have enough confidence to say that that's right,” Rumsfeld says. “I think that it's possible. We had [an] enormous number of troops ready to go in. We had off-ramps if they weren't needed. It's hard to know. You know, the path you didn't take is always smoother."