Former US defense secretary Donald Rumsfeld has said that George W. Bush was wrong to try and push democracy on Iraq and that NATO has become unfit to deal with modern threats and should be replaced by a more global alliance to fight Islamist extremism.

Rumsfeld’s remarks, made in an interview with The Times, mark a rift between the views of his then commander-in-chief, President Bush, who tried to push democracy right across the Middle East in the aftermath of toppling Saddam Hussein in 2003, although Rumsfeld apparently did nothing at the time to assuage his concerns.

“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 also said that NATO and the UN were no longer capable of coping with modern threats such as Islamic extremism, chemical weapons, Iran, and slavery, and instead said there should be a coalition of “right thinking” nations from across the globe.

He also expressed doubts that the West would easily be able to defeat Islamic State (IS, formerly ISIS/ISIL) and said a new Cold War style offensive was needed against the group.

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He warned that Arab nations are disintegrating, and said that the West’s airstrikes in Libya had served to further destabilize the region.

“The movement for a caliphate, the movement against nation states is central and fundamental. And no one’s talking about it. Have you ever heard anyone at the UN begin to think about that concept?” he asked.

He pointed the finger at President Obama, saying he had failed to show leadership and that this was having an effect both in the Middle East and in the Ukraine conflict.

“We can’t police the world, it’s too big, but people want to know what to think about their futures and the risks. Leaders need to tell them what is happening and have the guts to stand up and say, ‘This is what I think.’”

“If leaders aren’t willing to do it, why the hell should a guy with a wife and kids in the community put himself at risk?” he added.

He predicted that IS would take decades to defeat and that it was about countering their ideology rather than bullets and airstrikes.

“You begin to look at this thing not like a war but more like the Cold War ... you’re not going to win this with bullets, you’re in a competition of ideas. You’re going to have to squeeze down bank accounts, to find out who’s teaching whom what, to find ways to promote and encourage moderates,” said Rumsfeld, in his office at the Rumsfeld Foundation, an educational organization.