Sen. Tom Cotton (R-AR) unloaded on President Barack Obama, Vice President Joe Biden, Secretary of State John Kerry, former Secretary of State and likely 2016 Democratic presidential candidate Hillary Clinton, and the mainstream media over the Iranian nuclear deal—and the letter of 47 Republican senators he led about it—in an exclusive interview on Thursday morning with Breitbart News.

Cotton, a U.S. Army veteran, is the youngest member of the U.S. Senate (age 37) and defeated sitting Democrat Mark Pryor last election. This first big battle has created a firestorm that the bold southern conservative is handily winning against the entire political establishment.

“Any claim whether from the president, his cabinet members or from the media for that matter that this [the letter] is unprecedented is wrong but more importantly what’s really unprecedented is an American president negotiating a nuclear weapons deal with the world’s leading state sponsor of terrorism and not seeking congressional approval for it,” Cotton said when asked about the vitriol spewing from the left about his letter.

One reason we sent the letter is we wanted to be crystal clear that Iran’s leaders got the message. That message may not be communicated to their negotiating team in Geneva, the negotiating team may not communicate it back to Ayatollah Khamenei and his senior advisers.

We wanted to be sure that they understood the basic facts of our constitutional system, that the president negotiates deals but the Congress approves them. If Congress doesn’t approve a deal, then Congress doesn’t have to accept a deal.

Cotton detailed, too, for Breitbart News why the Obama deal with Iran is bad news—and why it shouldn’t go through. Cotton cited Israeli Prime Minister Benjamin Netanyahu’s address to a joint session of Congress earlier this month:

As Prime Minister Netanyahu said in his speech, the proposed terms of the deal doesn’t block the path to the bomb for Iran—it paves the path. Iran could get a nuclear weapon by breaking the deal, or by keeping the deal.

The first critical term is the 10-year sunset clause which Barack Obama said last week was acceptable to him. The second critical term is the vast nuclear infrastructure that Susan Rice said last week they could accept Iran having, in particular the enrichment of uranium for which Iran has neither a right nor a need.

Those two clauses combined—a sunset and a vast nuclear infrastructure—means that Iran might break the deal in the next 10 years and get a nuclear weapon, but they might simply keep the deal for the next 10 years and get a nuclear weapon. It only took North Korea 12 years to get a nuclear weapon from the time we reached the agreed framework in 1994 to the time they tested their first weapon in 2006.

Moreover, the terms of the negotiations from the very beginning have excluded critical topics like ballistic missiles for which Iran has only one need which is to strike the United States. And Iran continued to thwart the IAEA [International Atomic Energy Agency], the United Nations nuclear watchdog, and its efforts to explore the possible military dimensions of Iran’s nuclear program.

Whatever the terms of the final deal may be, the terms that President Obama himself has already foreshadowed make it an unacceptable deal that puts Iran on the path to a nuclear weapon. What we are focused on is stopping them [Iran, from getting a nuclear weapon], not just today or tomorrow, but 10 years or 15 years from now.

Cotton earlier this week led a letter that 46 of his GOP colleagues signed. He brought together Senate Majority Leader Mitch McConnell and Republicans with different viewpoints, from Sens. Lindsey Graham (R-SC) to Rand Paul (R-KY). The open letter, addressed to “the Leaders of the Islamic Republic of Iran,” explains that any deal Obama cuts with the Ayatollah could easily be undone via the stroke of a pen by the next president of the United States.

“It has come to our attention while observing your nuclear negotiations with our government that you may not fully understand our constitutional system,” the Cotton-led GOP letter reads. “Thus, we are writing to bring to your attention two features of our Constitution—the power to make binding international agreements and the different character of federal offices—which you should seriously consider as negotiations progress.”

The letter details how under the U.S. Constitution, “while the president negotiates international agreements, Congress plays the significant role of ratifying them” and in the case of a treaty the U.S. Senate “must ratify it by a two-thirds vote.”

“A so-called congressional-executive agreement requires a majority vote in both the House and the Senate (which, because of procedural rules, effectively means a three-fifths vote in the Senate),” the letter continues.

Anything not approved by Congress is a mere executive agreement. Second, the offices of our Constitution have different characteristics. For example, the president may serve only two 4-year terms, whereas senators may serve an unlimited number of 6-year terms.

As applied today, for instance, President Obama will leave office in January 2017, while most of us will remain in office well beyond then—perhaps decades. What these two constitutional provisions mean is that we will consider any agreement regarding your nuclear-weapons program that is not approved by the Congress as nothing more than an executive agreement between President Obama and Ayatollah Khamenei.

The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of the agreement at any time.

Seven Republican senators did not sign the letter, including Sens. Thad Cochran (R-MS), Bob Corker (R-TN), Lamar Alexander (R-TN), Lisa Murkowski (R-AK), Dan Coats (R-IN), Susan Collins (R-ME) and Jeff Flake (R-AZ). No Democrats signed the letter, though Cotton did tell Breitbart News some agree with its contents.

“I and my office reached out to some Democratic offices who we thought were sympathetic to the viewpoints,” Cotton said.

Some Democrats were on the record saying they agreed with the viewpoints: It’s very simply, how could you not agree with the fact that Congress has to approve international agreements for them to be binding, and that our founding fathers gave senators longer terms so they could have a longer view of our national security interests?

I would say it’s less of a partisan matter than a separation of powers matter because the president and his senior aides are putting extreme pressure on Democrats in the Congress to do nothing—nothing—to put any constraints on his negotiations, don’t sign the letter, don’t sponsor legislation, don’t vote for legislation.

The president’s position is Congress can’t vote after the deal is struck and they can’t vote before the deal is struck. He’s doing that in part because he knows the deal is unacceptable. He and his allies are on the defensive because the terms of the deal are indefensible. And 71 percent of the American people agree with us as indicated by a Wall Street Journal poll this week.

The letter has resulted in a media firestorm.

The New York Daily News ran photos of Cotton, Paul, McConnell and Sen. Ted Cruz (R-TX) earlier this week on the front page calling them: “TRAITORS.” CNN questioned whether the signers broke the law. The Washington Post’s Dana Milbank wrote a vicious column arguing that Republicans “appear set on their own breakaway nation.” And so many more in the media have been even more vicious in their attacks.

On Monday night, in response to the Iran letter, Vice President Joe Biden attacked Republicans including Cotton for writing it.

“In 36 years in the United States Senate, I cannot recall another instance in which senators wrote directly to advise another country — much less a longtime foreign adversary — that the president does not have the constitutional authority to reach a meaningful understanding with them,” Biden said.

Clinton used a press conference at the United Nations—one where she was supposed to be discussing her longtime use of a private email account and secret server system—to attack Cotton as well.

“One has to ask, what was the purpose of this letter?” Clinton said at the Tuesday press conference. “There appear to be two logical answers. Either these senators were trying to be helpful to the Iranians or harmful to the commander-in-chief in the midst of high-stakes international diplomacy. Either answer does discredit to the letter’s signatories.”

Cotton told Breitbart News he was “surprised” and “disappointed” Clinton said what she did, noting too that Clinton’s foreign policy failures in Libya—which had been disarming its nukes before she pushed for the U.S. to take out dictator Muammar Qaddafi—call into question her judgment on the matter of forcing a foreign dictatorial regime to disarm nuclear weapons.

“I was surprised and frankly disappointed in what Secretary Clinton said this week,” Cotton said.

Libya’s disarmament is an example of what Iran could do if it wanted to disarm its nuclear weapons: Complete unconditional nuclear disarmament. It’s also an example of how we could force Iran to disarm its nuclear program because Qaddafi did that after the Iraq war.

He was afraid that he might be next. The way to disarm rogue regimes is not to conciliate and grant them concessions but to confront and challenge them on every front. If you give sanctions relief, as President Obama has already done to Iran, it will let Iran extend its regional dominance into Iraq and Syria and Lebanon and Yemen—but to tighten the screws on sanctions, that’s what I would have done from the very beginning, and that would have been a much more effective way to achieve the goal that we all have which is the ultimate and complete nuclear disarmament of Iran.

Obama himself accused the Republicans who signed the letter of aligning themselves with Iran’s “hardliners.”

“I think it’s somewhat ironic to see some members for Congress wanting to make common cause with the hard-liners in Iran,” Obama said in response to Cotton’s letter. “It’s an unusual coalition.”

When asked if, since he’s the one negotiating a non-binding deal that many believe will help Iran eventually achieve nuclear weapons capabilities if Obama is the one aligning with Iranian “hardliners” and the one who deserves headlines accusing him of being a traitor, Cotton told Breitbart News that Obama is “paving the path” for Iran to build a nuclear weapons arsenal.

“First, I would say, there are nothing but hardliners in Tehran. President Obama, likes liberals throughout the Cold War, keeps looking for the vaunted moderates in totalitarian regimes that never seem to emerge,” Cotton said.

Second, President Obama is the one who’s paving the path for Iran to get a nuclear weapon. That is their goal, to get a nuclear weapon. President Obama’s own terms that he has foreshadowed would help put Iran on a path to get a nuclear weapon. The administration is in complete disarray.

On Monday night, Vice President Biden was saying this would be a binding deal and Congress didn’t need to play a role in it. Just 36 hours later, John Kerry was saying it wouldn’t be legally binding. But President Obama is the one whose deal is going to let Iran—which is governed by nothing but hardliners who have been killing Americans for 35 years including hundreds of troops in Iraq—get a nuclear bomb.

Iranian foreign minister Mohammad Javad Zarif had called the GOP letter “mostly a propaganda ploy” before, but on Thursday Ayatollah Khamenei said it showed “disintegration” in Washington.

“Of course I am worried, because the other side is known for opacity, deceit and backstabbing,” Khamenei said. “Every time we reach a stage where the end of the negotiations is in sight, the tone of the other side, specifically the Americans, becomes harsher, coarser and tougher. This is the nature of their tricks and deceptions.”

On Wednesday, Kerry admitted that the content of the letter are accurate—essentially undercutting the entire mainstream media and Democratic attack lines against Cotton and other Republicans.

“Secretary Kerry, what he admitted is that they are negotiating a legally non-binding deal and acknowledged the very basic point that I and 46 other senators made in our letter that if President Obama does not submit this deal for approval to Congress then a future president can rescind it with the stroke of a pen as President Obama himself has done on other executive agreements and future Congresses can vote to modify or act to rescind it as well,” Cotton said in his Thursday interview with Breitbart News.

“I’m glad that Secretary Kerry clarified it but I’m also very troubled by the fact that they’re negotiating a legally non-binding deal which means that Iran could also change it any time. We could get billions of dollars of sanctions relief from a sanctioned regime, and in a year or two years Ayatollah Khamenei or his successors could simply say ‘we’re walking away from the deal.’”

Cotton said that if Obama goes through with this deal without congressional approval—as the president appears hell-bent on doing—that Congress must do everything in its power to stop him. He said he’s prepared to do that.

“One thing that unites Democrats and Republicans in Congress alike is the fact that Congress must weigh in on this deal,” Cotton said.

There may be disagreements about the terms of the deal among us, but I for one certainly would not support a deal that gave Iran a vast nuclear infrastructure and had a sunset of as little as 10 or 15 years. I would do everything within my constitutional power in this office to stop that deal from coming forward. As President Obama himself has said on countless occasions, no deal is better than a bad deal. What he’s proposing right now is a very bad, very dangerous deal.