As President Obama seeks out a reluctant China and Russia to help press Iran on ending its nuclear program, one Republican senator said he’d be willing to take the U.S. into war with Iran to prevent it from attaining nuclear weapons capabilities.

“Totally. Absolutely without any doubt the Iranians if they develop a nuclear weapon … the whole region is going to want a nuclear weapon. Then you march down the road of Armageddon,” Sen. Lindsey Graham, R-S.C., said Sunday.

“If you open Pandora’s box, if you attack Iran, if they get a nuclear weapon you empty Pandora’s box, that’s the world we live in. So I support the option of a military option as a last resort.”

But Graham warned that Iran has progressed so far in its belligerence know-how that just cutting off its nuclear program isn’t going to do the trick.

“Their capability is so redundant you’d have to do more than go after the nuclear program, you have to neuter this regime, destroy the air force, sink their navy, go after the Revolution Guard and try to get people in the country to overthrow the regime. We need a regime change. If they get a nuclear weapon the world is going to go into darkness,” he said on CBS’ “Face the Nation.”

Graham’s warnings came after President Obama met with Russian and Chinese leaders on Saturday to seek their support for more sanctions against the Islamic Republic, which has threatened to drop its membership in the U.N.’s International Atomic Energy Agency following a report about Iran’s nuclear weapons pursuit.

The report stated that the program Iran alleged to have cut off in 2003 is back on again, and while it doesn’t have the ability to put a nuclear warhead on the end of a ballistic missile, it does have the ingredients and is in active pursuit.

Tehran called the report untrue. National Security Council Spokesman Ben Rhodes, traveling with President Obama to the Asian-Pacific Economic Cooperation conference in Hawaii, said there’s nothing to doubt.

“This is not simply the judgment of the United States or any one country. This is the finding of the preeminent international organization that deals with these issues. Therefore it’s essential that the international community take those findings very seriously,” Rhodes said.

At APEC, Obama met with his Russian and Chinese counterparts to discuss what to do with the country. Russian President Dimitri Medvedev agreed on the threat, but not the response.

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