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"I do believe that negotiation is better than war," Paul told TODAY's Savannah Guthrie in an exclusive interview. "What I would say is that there has always been a threat of Iran gaining nuclear weapons, and I think that's greater now than it was many years ago. I think we should do everything we can to stop them."
Paul is the second U.S. senator to formally announce a White House run, following Ted Cruz, who announced his bid last week.