In his 29 years as a Democratic senator from Massachusetts, Kerry said, he 'never heard of or even heard of being proposed anything comparable to this.' Kerry in 'utter disbelief' over GOP letter to Iran

Secretary of State John Kerry says he’s in “utter disbelief” over the letter to Iranian leaders led by Sen. Tom Cotton of Arkansas and signed by 46 other Republican senators warning any Iranian nuclear deal reached with the U.S. could be revoked by the next president or modified by Congress.

“This letter ignores more than two centuries of precedent in the conduct of U.S. foreign policy,” Kerry said Wednesday at a Senate Foreign Relations Committee hearing. “This risks undermining the confidence that foreign governments in thousands of important agreements commit to with the United States.”

In his 29 years as a Democratic senator from Massachusetts, Kerry said, he “never heard of or even heard of being proposed anything comparable to this.” He said senators have the right to voice dissent but doing so in a letter to foreign leaders was “quite stunning.”

Kerry, who once chaired the Foreign Relations Committee, also said the letter was factually incorrect.

“It’s incorrect when it says that Congress could actually modify the terms of the agreement at any time,” he said. “They don’t have the right to modify an agreement reached, executive to executive, between the leaders of two countries.”

During the hearing, Sen. Marco Rubio also tangled with Kerry over the issue of Iran’s influence in the U.S. fight against the Islamic State.

The Florida senator, who is weighing a campaign for the Republican presidential nomination, said he believes much of the U.S. strategy in Iraq and Syria is “being driven” by a desire not to upset Iran amid sensitive nuclear negotiations.

“Because the facts completely contradict that,” Kerry shot back.

Kerry said many of the details about the negotiations were classified but noted the talks were designed to curtail Iran’s nuclear program — and the administration wasn’t trying to reach a “grand bargain” that would normalize relations with the Islamic Republic.

“This is about a nuclear weapon — that’s it,” Kerry said.

Rubio, whose experience on the Foreign Relations panel could bolster his stature in a 2016 GOP presidential field that lacks a lot of foreign policy experience, also pressed Kerry on whether the negotiations with Iran were hurting U.S. ties to its Arab allies in the Middle East.

Kerry responded that he was keeping U.S. allies in the region updated on the status of the talks.

CLARIFICATION: This report has been updated to reflect Kerry’s exact wording. He said, “Because the facts completely contradict that.”