Secretary of State John Kerry took to the Senate floor on Thursday to defend the recently negotiated Iran nuclear deal against skeptical lawmakers. Kerry told lawmakers that he believed this plan is the only hope to curb Iran's nuclear capabilities, and warned that if the U.S. were to walk away from the plan that is a culmination of nearly 20 months of negotiations, it would severely tarnish the country's reputation on the world stage. "If the U.S., after laboriously negotiating this multilateral agreement with five other partners, were to walk away from those partners, we're on our own," Kerry told the Senate Foreign Relations Committee.