The Hill News

Donald Rumsfeld said Sunday that bad intelligence was his biggest worry while leading the country into Iraq.

The former Defense secretary said what kept him most awake at night was "the concern I had that the information we had was imperfect." 

"I've been around long enough and seen enough instances where the intelligence was wrong and where the information that later was learned didn't conform to what was expected," he explained on CNN's "State of the Union."

"And that certainly was the case here this time."

Rumsfeld was a driving force behind the U.S. invasion of Iraq in 2003, which the Bush administration characterized as a necessary step to protect Americans from Iraq's alleged stockpile of weapons of mass destruction (WMDs). Eight years and more than 4,400 U.S. deaths later, that war rages on. No WMDs were ever found. 

Rumsfeld pushed back Sunday against the notion that WMDs were the only reason behind the U.S. attack, telling CNN's! Candy Crowley "there were a variety of reasons for the war." 

"If you looked at the resolution from the Congress, there were multiple reasons," he said. "If you looked at the U.N. resolution, there were multiple reasons."

Still, he conceded that the WMD issue "was the big one."

Last week, in another embarrassing episode for the Bush administration, an Iraqi defector who supplied intelligence to Bush White House told a British newspaper that he'd lied about Iraq's weapons to instigate a U.S. invasion.

"I had the chance to fabricate something to topple the regime," Rafid Ahmed Alwan â€" known more familiarly by his code name, "Curveball" â€" told The Guardian. "I and my sons are proud of that and we are proud that we were the reason to give Iraq the margin of democracy."

Rumsfeld defended the administration for leaning on Alwan's intelligence, arguing that it's "very difficult to determine intent."

"The intelligence community talks to hun! dreds of people," he said. "Some are honest, some are dishones! t. Some do it for money, some do it for self aggrandizement. Some do it, apparently, to lie." 

Rumsfeld also praised the Obama administration for reversing course on campaign pledges to dismantle a number of Bush-era detention programs â€" positions that have drawn fire from Obama's liberal base.

"They now have switched from the campaign mode, and they are keeping Guantanamo Bay; they are keeping indefinite detention; they are keeping military commissions," Rumsfeld said. "So obviously, they've come to the conclusion that … [it's] easier to campaign than it is to govern." 

As Congress wrestles with ways to rein in deficit spending, Rumsfeld suggested there's plenty of room for cuts in defense. 

"Every year the Congress was stuffing $10 billion down the Pentagon's throat that we didn't want," he said. "There's no question that there's money there." 

The former Defense secretary has been touring the country to promote a new book: "Known and Unknown:! A Memoir." The proceeds will go to wounded soldiers and their families.