(CNN) -- Republican presidential hopeful Rudy Giuliani Wednesday said he would be open to diplomatic talks with Iran but only if certain preconditions were established.
Rudy Giuliani says he would permit waterboarding only in a "once-in-a-lifetime" situation.
"I would want to make sure there was a chance it would work," Giuliani told CNN's Wolf Blitzer in Columbia, Missouri. "I would want to make sure there would be an opportunity to verify whatever it is we were going to do."
"I worked for Ronald Reagan. I believe in 'trust but verify,' " he said.
Iran, which the United States considers to be a state sponsor of terrorism, has been under pressure from the U.S. and the international community to suspend its development of nuclear technology.
Giuliani, the former mayor of New York, suggested he would meet Iranian President Mahmoud Ahmadinejad, but only if preconditions were established, noting that President Reagan met with America's adversaries.
"He spoke to the Russians, Soviets, the Chinese," Giuliani said. "Even at the highest level of the Cold War, there were discussions, but not without preconditions."
If he did enter into talks with Iran, an American invasion of Iran to topple the current Islamic government would not be off the table, Giuliani said.
"Some have said they would take regime change off the table or they seem to be less firm about the military option. You start taking these things off the table, there's no negotiation, there's no pressure, no leverage. You have to have leverage," Giuliani said.
During the interview, Giuliani also said waterboarding should not be used in interrogations, but he opened the door to using it in a "once-in-a-lifetime, once-in-a-decade situation." Watch Giuliani talk about the president he would be »
"Having looked at this, it certainly should not be a practice that should go on generally," he said.
But Giuliani said there may be situations where waterboarding, a technique in which a person undergoes simulated drowning, would be warranted to obtain critical information, such as when a terrorist knows the location of a nuclear bomb that is about to explode.
Many human rights organizations consider waterboarding to be torture.
"I don't think you can write this out as a procedure that should be written out for all situations," Giuliani said. "I think the president and the appropriate officials should have some discretion here." E-mail to a friend