A group of 47 Republican senators warned Iran's mullahs on Monday that any agreement the Obama administration strikes with the Islamic republic to limit Tehran's nuclear program may be short-lived unless Congress formally approves it. In a rare open letter to Iranian leaders, Arkansas freshman Sen. Tom Cotton and 46 others from the GOP wrote that without congressional approval, '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,' the Republicans wrote, 'and future Congresses could modify the terms of the agreement at any time.' The White House in turn tried to brand Republicans as warmongers and accused them of pursuing a 'partisan strategy to undermine the president' while demanding power that goes against the role the Founding Fathers envisioned the legislative branch playing in foreign affairs. SCROLL DOWN TO READ THE LETTER . Freshman Sen. Tom Cotton of Arkansas, shown in January at the US Capitol, organized 47 Republican senators to warn Iran that a nuclear agreement could be short-lived unless Congress approves it . The White House in turn tried to brand Republicans as warmongers and accused them of pursuing a 'partisan strategy to undermine the president' while demanding authority that goes against the role the Founding Fathers envisioned the legislative branch playing in foreign affairs . Secretary of State John Kerry (third from left) met with Iranian Foreign Minister Mohammad Javad Zarif (third from right) for a new round of nuclear negotiations last wek while Israeli Prime Minister Benjamin Netanyahu was in Washington telling Congress that Tehran can't be trusted . 'The rush to war, or at least the to the military option that many Republicans are advocating is not at all in the best interest of the United States,' White House spokesman Josh Earnest said Monday afternoon. Earnest speculated that letter emanated from Senate Republicans' concern that as soon as a deal is signed, the White House would begin pressuring Congress to begin lifting sanctions. The White House would first want to see 'demonstrated compliance' on the part of Iran before that would ever happen, the president's spokesman said. 'The president does not envision substantial sanctions relief for Iran right at the negotiating table.' It will not even be weeks or months before such a conversation would take place, he explained. 'I'm talking about years.' The single-page letter at no point makes reference to sanctions - or war, for that matter. Republicans and Democrats alike have said they would like to see a stricter sanctions regime enforced if Iran does not agree to the United States' terms by the end of the month, and a resolution to that effect is set to come to the floor of the Senate. That legislation would not authorize the president to go to war with Iran, though . Still, Earnest contended that letter signers have no alternative to President Barack Obama's diplomatic strategy other than 'a military option.' 'If they want to mask it as part of some sort of civics lesson that they want to share with Iran's political leadership, they're welcome to do that,' he said. 'It might evince some reluctance or at least hesitations about the wisdom of their strategy, or at least the wisdom of their ultimate goal here,' he charged. He added: 'The efforts of neoconservatives in the previous administration to do that frankly hurt the country's standing around the world.' Speaking to reporters after a meeting in the Oval Office with European Council President Donald Tusk, Obama commented that it's 'somewhat ironic' that Republicans want to align themselves with 'hardliners' in Iran. 'It's an unusual coalition,' he said. ON NOTICE: The letter to Iran's supreme leader Ayatollah Ali Khamenei (pictured) warns that senators who signed it will be in office long after President Barack Obama leaves the White House . Later in the briefing he brought up an Authorization for the Use of Military Force agreement the White House sent to Congress last month asking for the power to fight ISIS with ground troops in special circumstances. Some Republicans complained that the legislative language would bind the president too tightly because it strictly prohibited an 'enduring' deployment of US forces. 'We see a Republican Party that is eager to.... direct almost unlimited authority to the President of the United States to wage war, but to try to repeatedly tie his hands when he is trying to conduct diplomacy,' Earnest claimed. The President would rather use America's influence to try to build coalitions around the world, not only because he thinks it is 'more effective,' Earnest said, but because it 'has yielded important results for the American people.' He cited the global coalition to destroy ISIS as an example. 'There is a starkly different approach between the one that is advocated by Republicans that puts the military option and war-fighting at the top of the list,' he continued. 'That is not an approach that the vast majority of the American public support, and it's certainly not an approach that our recent history indicates is the best way to protect American national security interests.' The U.S. and other nations are seeking a pact that would let Western powers verify that Iran will not obtain a nuclear weapon. Although the letter, first reported by Bloomberg, is addressed to 'Leaders of the Islamic Republic of Iran,' it's equally aimed at delivering a message to Obama. 'The president may serve only two 4-year terms, whereas senators may serve an unlimited number of 6-year terms,' Cotton's group wrote. '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.' Cotton told Bloomberg that 'Iran's ayatollahs need to know before agreeing to any nuclear deal that … any unilateral executive agreement is one they accept at their own peril.' California Sen. Dianne Feinstein said Monday after that she was 'appalled' at the Republican effort to 'blow up a major effort by our country and the world powers to negotiate a peaceful resolution to the Iranian nuclear program.' 'This is a highly inappropriate and unprecedented incursion into the president’s prerogative to conduct foreign affairs,' she said. 'This letter only serves one purpose—to destroy an ongoing negotiation to reach a diplomatic agreement in its closing days.' The White House said Monday that the Republican senators's move 'certainly interferes' with ongoing negotiations. Their effort to 'essentially throw sand in the gears here is not helpful,' Earnest said, and is not 'the role our Founding Fathers envisioned Congress for to play when it comes to foreign affairs.' He told reporters the letter raises 'legitimate' questions about the 'intent' of Republican lawmakers. In remarks on the Senate floor Monday afternoon top-ranking Democrat Harry Reid said the judgment of the chamber's Republicans 'seems to be clouded by their abhorrence of President Obama.' Reid, who was the Senate's majority leader until January, when Republicans rose to power, said the letter signers were 'undermining' Obama 'while empowering the Ayatollahs.' 'It is unprecedented for one political party to directly intervene in an international negotiation, with the sole goal of embarrassing the President,' he stated. 'We as leaders should do everything we can to ensure these negotiations have a chance to succeed. When it comes to preventing Iran from obtaining a nuclear bomb, we should put partisanship aside.' Reid said that most Senate Democrats disagreed with President George W. Bush’s foreign policy, but they never even 'considered' sending a letter to Saddam Hussein because 'it would have been an embarrassment.' 'Obviously Republicans don’t know how to do anything other than attempt these seemingly juvenile political attacks against the President,' he said, attacking his successor, Mitch McConnell's ability to govern. The uranium enrichment facility in Natanz, Iran is a major sticking point with the US, which wants inspectors to have unfettered access to the Iranian regime's nuclear program . 'The greatest threat against the world is the marriage of militant Islam with nuclear weapons,' Israeli Priime Minister Benjamin Netanyahu warned Congress last Tuesday . Israeli Prime Minister Benjamin Netanyahu addressed a joint meeting of Congress last week in Washington. 'The greatest threat against the world is the marriage of militant Islam with nuclear weapons,' he warned lawmakers. Republicans and some Democrats want Congress to have a vote on any agreement. The pact the bargainers are working on does not actually require congressional approval, however, because it is not a treaty, which would require a two-thirds majority Senate vote to be ratified. Last week Senate Majority Leader Mitch McConnell, a Kentucky Republican, postponed action on legislation that would give Congress a vote on any deal that emerges. He delayed the measure in the face of solid Democratic opposition to moving ahead on the bill now, just weeks before an end-of-March deadline for negotiators to produce an outline of an agreement. On CBS' 'Face the Nation' Sunday, McConnell said the president would need congressional approval to lift sanctions already imposed on Tehran because of its nuclear program. 'I think he cannot work around Congress forever,' McConnell said. Obama said in a separate CBS interview that the U.S. would 'walk away' from the talks unless they produce a procedure for verifying that restrictions on Iran's nuclear effort are working. The letter released Monday was signed by 47 of the Senate's 54 Republicans. Included were McConnell and the rest of the Senate GOP plus presidential contenders Marco Rubio of Florida, Rand Paul of Kentucky and Ted Cruz of Texas. The next negotiations are scheduled for March 15, and wide gaps remain between the two sides. Iran has said its nuclear program is peaceful and is aimed at producing energy. The Associated Press found no discussion of the letter in Iranian media, and Iran's regime had no immediate response to it. Cotton serves on the Senate's Armed Service and Intelligence committees. He said Monday morning on the Fox News Channel that Iran is a bigger threat to the U.S. than the ISIS terror army operating in Iraq and Syria. He also said he would like to see some Democrats sign on to his letter. 'I'd encourage Hillary Clinton to join us,' he said. Tom Cotton Open Letter to Iran uploaded by DailyMail.com .
'The rush to war, or at least to the military option that many Republicans are advocating is not at all in the best interest of the United States,' White House spokesman Josh Earnest said Monday afternoon . Obama commented that it's 'somewhat ironic' that Republicans want to align themselves with 'hardliners' in Iran. 'It's an unusual coalition'
Arkansas Sen. Tom Cotton organized 46 other GOP senators to sign on to an open letter to Iran's mullahs . Warned against inking an Iran-US nuclear deal without congressional approval . President Obama's successor 'could revoke such an executive agreement with the stroke of a pen,' the letter read . 'Future Congresses could modify the terms of the agreement at any time'
Republicans' judgement 'seems to be clouded by their abhorrence of President Obama,' the Senate's highest ranking Democrat accused .