Former vice president Dick Cheney said the security of policies of the Bush administration had protected the U.S. since the September 11 attacks and warned of a high probability that much deadlier attacks could take place if those policies were not kept in place.

Cheney issued the statement during an interview with politics news site Politico defending the previous presidential administration's efforts to combat terrorism.

If it hadn't been for what we did — with respect to the terrorist surveillance program, or enhanced interrogation techniques for high-value detainees, the Patriot Act, and so forth — then we would have been attacked again, he said. Those policies we put in place, in my opinion, were absolutely crucial to getting us through the last seven-plus years without a major-casualty attack on the U.S.

President Barack Obama, just days into his administration is undoing some of those policies, including banning the military's use of torture, and vowing to close the Guantanamo Bay prison which houses hundreds of enemy combatants.

Some of those detainees were in the process of being tried through special military tribunals set up by the Bush administration. President Obama believes the existing U.S. federal criminal justice system should be used instead.

Cheney said the 'ultimate threat to the country is 9/11 type event where the terrorists are armed with something much more dangerous than an airline ticket and a box cutter – a nuclear weapon or a biological agent of some kind that is used in an American city.

He said such an attack would kill hundreds of thousands of people, and the one you have to spend a hello of a lot of time guarding against.

I think there's a high probability of such an attempt. Whether or not they can pull it off depends whether or not we keep in place policies that have allowed us to defeat all further attempts, since 9/11, to launch mass-casualty attacks against the United States.