A group of 47 Republicans wrote an open letter to Iran yesterday warning that any nuclear deal with US President Barack Obama will not last after he leaves office in January 2017.
"It has come to our attention while observing your nuclear negotiations with our government that you may not fully understand our constitutional system… Anything not approved by Congress is a mere executive agreement," the senators wrote.
"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," they said.
The letter comes only one week after Israeli Prime Minister Benjamin Netanyahu delivered a speech at Congress in which he warned that the United States was negotiating a "bad deal" with Tehran.
Republicans want the Congress to have a say in any potential nuclear agreement with Iran.