The US considers itself "safer" than after the September 11, 2001 terrorist attacks, but "not yet safe" despite its successes like disgraced Pakistani scientist A.Q. Khan's nuclear black market going out of business.
"Let me not speak to the nuclear issue, but we're safer than we were on September 11 in general, but we are not yet safe," US Secretary of State Condoleezza Rice said in an address at the Heritage Foundation, a conservative think tank on Wednesday.
"There is no worse nightmare than the bringing together of terrorism and weapons of mass destruction. It is one reason that I think we've worked so hard on the non-proliferation piece," she said when asked how safe the US was from a nuclear attack.
"And we have had successes. Libya is out of the business, verifiably. The A.Q. Khan network, about which we're continuing to learn more, is at least out of the business," Rice said without referring to new revelations about the father of Pakistan's atomic bomb.
A study by the Institute for Science and International Security has suggested that an international smuggling ring once run by A.Q. Khan may have given Iran - and other nations - blueprints for a miniature nuclear warhead first developed for his country's programme.
"We can, I believe, deal with what North Korea has produced in terms of materials that might be proliferated and put a collar around it of the other five parties to try to keep it from proliferating. So time and time again, the administration has stepped up about proliferation issues. We do it because it's important, but we also do it because anybody's worst nightmare is that nexus of terrorism and weapons of mass destruction," Rice said.
"As the memories of September 11 have faded, we feel safer," she said. "But if we're going to stay safer, it requires extraordinary vigilance, it requires extraordinary defensive measures, but it also requires meeting them on their own turf.
"And that's why dealing with the root causes in places like the Middle East, working with allies, whether it's Pakistan or Saudi Arabia or others, to root out terrorism at its core - this is the great struggle," Rice said.