Congressional moves to weigh in on Iranian sanctions could jeopardize nuclear talks and derail years' worth of efforts to open negotiations, Secretary of State John Kerry said Thursday during a Morning Joe exclusive interview.
"We respectively believe that the executive branch of government under the Constitution deserves the right to negotiate and present them with something, and that this is not the moment to second guess that process," he said on the show. "You have to do something in order to make it worthwhile for them to say, 'Yes, we're going to lock our program where it is today and actually roll it back.'…If we don’t negotiate and we don’t get this agreement, the exact opposite happens.”
Conversations with Iran over its nuclear program stalled over the weekend, but a new round of talks will begin next week.
Kerry along with Vice President Joe Biden urged senators on Wednesday to trust leaders can reach an agreement with Iran to halt the expansion of its nuclear programs, and hold off on new sanctions against the country.
The secretary of state asked lawmakers on Wednesday to "calm down" over proposed new sanctions, warning they could harm diplomatic efforts.
"The risk is that if Congress were to unilaterally move to raise sanctions, it could break faith with those negotiations and actually stop them and break them apart," Kerry said earlier this week.
Related: U.S. faces resistance from allies on Iran
U.S. officials remain "hopeful" about reaching a deal with the West Asian country, he said on Thursday. But it is now critical to focus on the centerpiece of President Obama's policy that under no circumstances will Iran gain access to a nuclear weapon.
"What we're really asking the Congress to do is give us the time to be able to negotiate and present a good deal that will be able to protect Israel, protect our interest, protect the region, and guarantee--I mean guarantee--fail-safe that Iran will not be able to get a nuclear weapon. It’s a pretty simple proposition," said Kerry.
Israel Prime Minister Benjamin Netanyahu favors increasing the sanctions and putting further pressure on Iran. But U.S. officials disagree with the tactic.
Kerry on Thursday said he has had "friendly and civil" conversations with Netanyahu, and he "respects completely" the prime minister's deep concerns about the existential nature of the threat of Iran's weapons to his country.
"We believe that you need to take this first step and that you will not get Iran to simply surrender and believe you’re dealing in good faith if after two years of negotiating you don’t follow through with what's on the table," Kerry said on the show.
"We stand with Israel firmly, 100%," he added. "The end game for us is exactly the same: Iran cannot have a peaceful nuclear program...There must be absolute clarity of the processes which will guarantee it is a peaceful program, that’s our mutual goal.”