Exclusive: Mitt Romney on Iran: President Rouhani is not calling the shots

Iranian President Hassan Rouhani has made several moves recently, indicating the beginning of a new era in U.S.-Iran relations. On Friday, President Barack Obama spoke by telephone with Rouhani, the first direct conversation between leaders of the United States and Iran since 1979.

But in an exclusive interview with CNN’s Jake Tapper, 2012 Republican presidential nominee Mitt Romney said the U.S. should keep its guard up when it comes to Iran.

"You have to be skeptical when people say, 'We're just looking for nuclear power,' when their nation is on a lake of oil," Romney said in the interview conducted on Friday in Boston.

"(Rouhani) really doesn't set the nuclear policy of his nation. That's done by Ayatollah Khamenei. And so, he doesn't actually have the capacity to call those shots," said Romney.

The U.S. should pursue a diplomatic opening with Iran "as aggressively as we can, but recognize again that there's a great deal of skepticism with regard to Iran's intentions, in part because of their energy wealth, and the likelihood that what they're trying to is to become the superpower in the Middle East, with dire consequences for the nations in the region," said Romney.

Supporters of the 2012 Republican presidential candidate have mentioned the name Mitt Romney frequently in recent weeks and months, reminding people that Romney was mocked during the election for calling Russia America's number one geopolitical foe. Vice President Joe Biden also criticized Romney on the campaign trail for wanting to start a war in Syria.

Given recent events, Romney supporters feel that their candidate has been vindicated.

"I'm vindicated in my own mind from the beginning," said Romney. "We recognize increasingly that Russia is not an enemy; it's certainly not a military combatant foe. But it is a political foe. The world's worst actors, whether it's North Korea, Cuba, Venezuela, Syria, Iran, are all supported and protected to some degree by Russia."

For more of our foreign policy interview with Mitt Romney, including what he learned from national security briefings, watch the video above.