Washington (CNN) — Former Defense Secretary Donald Rumsfeld now said that the goal of creating a democracy in Iraq was “unrealistic” and that he was “concerned” when he first heard the idea floated by former President George W. Bush, a stark admission by one of the Iraq War’s biggest defenders.

“I’m not one who thinks that our particular template of democracy is appropriate for other countries at every moment of their histories. The idea that we could fashion a democracy in Iraq seemed to me unrealistic. I was concerned about it when I first heard those words,” Rumsfeld told the Times of London last weekend.

The comments mark a rare departure for Rumsfeld, who has been one of the staunchest defenders of the Iraq War started by Bush, but also a sharp critic of President Barack Obama’s handling of it.

Rumsfeld also raised broader concerns that the global nation-state system faces a threat of replacement by Islamic caliphates and said that NATO and the United Nations may be unequipped to handle threats from Islamic extremists.

Rumsfeld, who served as Bush’s defense secretary from 2001 to 2006, said that removing former Libyan leader Moammar Gadhafi was a mistake because it destabilized the region, but defended the decision to eliminate Saddam Hussein.

The Iraq War and concerns over Middle East stability have returned to the forefront of the national debate with the ongoing battle with the Islamic State, or ISIS.

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