Illinois Sen. Mark Kirk was among 47 Republican senators who on Monday sent an open letter to the Iranian government suggesting they could undue whatever nuclear agreement to which President Barack Obama's administration agrees.
The letter reads, in part:
"…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 an agreement at any time."
The United States, along with five world powers, hopes to negotiate a framework agreement this month and a final accord later this year which would curb Iran's nuclear program in exchange for sanctions relief.
Kirk has warned that any relief in sanctions would lead to "more terrorism" and possibly war with Iran.
"The path of appeasers always leads directly to war -- it just increases the appetite of the other side," he said in January. "Appeasers always lead directly to war. You can give Czechoslovakia to Hitler and he wants more. If you give billions of dollars to the Iranians, you're probably leading directly to conflict."
Sen. Tom Cotton of Arkansas, the freshman lawmaker who drafted the letter, said he wasn't trying to undermine the president but simply wants to ensure Iran doesn't obtain or develop a nuclear weapon.
Kirk's Illinois counterpart in the Senate, Democratic Whip Dick Durbin, called the letter a "cynical effort" by Republicans to "undermine sensitive international negotiations."
"It weakens America’s hand and highlights our political divisions to the rest of the world. Understand that if these negotiations fail, a military response to Iran developing their nuclear capability becomes more likely. These Republican Senators should think twice about whether their political stunt is worth the threat of another war in the Middle East," he wrote in a statement posted to his Senate website.
Obama called the letter "ironic," and Vice President Joe Biden said it "ignores two centuries of precedent and threatens to undermine the ability of any future American president."
Iranian Foreign Minister Mohammad Javad Zarif told NBC News the letter "has no legal value and is mostly a propaganda ploy."