A political firestorm erupted late Monday after an open letter from Republican senators to Iran's leaders challenged President Obama's ability to strike a permanent nuclear deal with Tehran.
Vice President Joe Biden strongly denounced the letter in a statement saying the missive "offends me as a matter of principle" and was "beneath the dignity of an institution I revere."
"In thirty-six 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 in his statement.
The letter signed by Sen. Tom Cotton, R-Ark., and 46 of his colleagues warned Tehran that any nuclear deal needs congressional approval in order to last beyond Obama's term and pointed out that without that step, all Iran would be left with is a "mere executive agreement" between Obama and Ayatollah Ali Khamenei.
The letter added, "We hope this letter enriches your knowledge of our constitutional system and promotes mutual understanding and clarity as nuclear negotiations progress."