Sen. Bernie Sanders (I-Vt.) insinuated on Sunday that the nuclear deal struck with Iran and the diplomatic breakthrough that led to the release of four American hostages would not have happened had Hillary Clinton been president.

The statement on "Meet the Press" came just hours after the International Atomic Energy Agency verified that Iran had complied with the conditions of the deal struck with world powers last summer, and as the hostages were en route back to the United States.

“If you think back to, I think it was 2007, during the campaign in which Secretary Clinton ran against Barack Obama, she was critical of him. A question was asked to Obama and said, "Would you sit down and talk to the Iranians?" And he said, "Yeah, I would." Point being that you talk to your adversaries. You don't run away from that,” Sanders said.

“Secretary Clinton, I think, called him naïve. Turns out that Obama was right. So clearly, we have many, many issues and many concerns with Iran. But clearly also, we want to improve our relationships with this very powerful country.”

Here is the exchange from 2008:

The charge from Sanders -- that Clinton philosophically opposed the type of rapprochement that led to the nuclear deal and the prison swap -- ratchets up a relatively dormant foreign policy riff between the leading Democratic candidates (who have, to this point, primarily been duking it out on economic issues). But it also ignores the role that Clinton played in laying the foundations for the Iran nuclear deal.

It was during her time as secretary of state that the diplomatic shift towards Tehran began to take place. And it was her top foreign policy aide (and current campaign adviser) Jake Sullivan who began meeting in secret with Iranian officials in Oman. Both Clinton and Sullivan “were key players in the Iran deal,” as the Wall Street Journal reported.

The Clinton campaign did not respond to a request for comment.

But Clinton remains hawkish on Iran to this day, even calling for additional sanctions against Iran for its ballistic missile program in the aftermath of the prisoner swap. And Sanders’ campaign clearly senses some space between her and the Democratic base on the broad issue of how much to rely on diplomatic engagement when it comes to Iran.

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