Tom Cotton
U.S. Sen. Tom Cotton, R-Ark., organized an effort to write to Iranian leaders. The letter was signed by 47 Republican senators. Reuters

The Arkansas senator who drafted a letter sent to Iranian leaders to persuade Tehran not to agree to a nuclear deal and urge U.S. President Barack Obama to give Congress oversight of the negotiations fired back Tuesday against Vice President Joe Biden, who called the letter “beneath the dignity of an institution I revere.” In response, U.S. Sen. Tom Cotton, R-Ark., slammed Biden’s leadership on foreign policy issues during an appearance on MSNBC’s “Morning Joe.”

“Joe Biden, as [President] Barack Obama’s own secretary of defense has said, has been wrong about nearly every foreign policy and national security decision in the last 40 years,” Cotton said, according to Politico. The senator was referring to the memoir by former Defense Secretary Robert Gates, who criticized Biden in the book. “Moreover, if Joe Biden respects the dignity of the institution of the Senate, he should be insisting that the president submit any deal to approval of the Senate, which is exactly what he did on numerous deals during his time in Senate,” Cotton said.

Cotton and 46 other Republican senators signed a letter dated Monday that was addressed to Iranian leaders. It warned them that a potential deal with Obama and leaders of five other countries can be tossed out by the next U.S. president because such a deal would constitute an “executive agreement.”

Biden, who served for nearly four decades in the Senate and is a former chairman of the Senate Foreign Relations Committee, said the letter undermined Obama and the negotiations. He said the letter was inappropriate.

"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. This letter sends a highly misleading signal to friend and foe alike that our commander-in-chief cannot deliver on America’s commitments -- a message that is as false as it is dangerous," Biden said in a statement, according to the Huffington Post.

"The decision to undercut our president and circumvent our constitutional system offends me as a matter of principle. As a matter of policy, the letter and its authors have also offered no viable alternative to the diplomatic resolution with Iran that their letter seeks to undermine," Biden said.