According to a report by the National Public Radio on Tuesday, he said “if Congress or a future president reverses a nuclear control agreement with Iran, U.S. credibility will suffer.”

He was talking to the news website just after hosting Cuba’s foreign minister at the State Department.

Kerry defended the Obama administration's stance on both countries, and said if diplomatic relations with Cuba or a nuclear deal with Iran were scuttled — either by a future president or Congress — it would hurt the U.S.

He believed, “But I think it’d be a terrible mistake. The vast majority of the American people believe this is a very good thing to do. ... As time goes on, people will see the benefits that come from this policy.”

“We had diplomatic relations with the Soviet Union,” Kerry continued. “We had diplomatic relations with then-called ‘Red China.’ We have to have relationships with countries to do business. And American citizens get hurt when we don’t do that.”

According to the NPR, “On Iran, Kerry said if Congress failed to approve a nuclear deal with the country, the results would be disastrous. “I’m telling you, the U.S. will have lost all credibility,” Kerry told. “We will not be in the hunt. And if we then decided to use military [after a deal fails], do you believe the United Nations will be with us? Do you think our European colleagues will support us? Not on your life.”

Kerry said Iran would use the deal’s failure as an excuse to enrich uranium. “[The deal’s failure] will be a travesty, and Iran will begin enriching, claiming it is a right that they only gave up in the context of negotiations, but since negotiations are dead, they're going to resume their rights.”

He continued, Iran will say, “Aha, you see!” The Ayotollah will say, “I told you, you can’t trust the West. I told you, you can’t negotiate with these guys. They will lie to you. They will cheat you. And here they are, they let us down, and the Congress walked away. They have 535 secretaries of state. There’s nobody to negotiate with.”