Note to GOP: Your days are numbered.

WASHINGTON — Vice President Joe Biden is furious.

Biden, who also serves as president of the Senate, Monday night blasted Senate Republicans in a long, angry statement for their letter to Iran’s leaders, which he described as “beneath the dignity of an institution I revere.”

Forty-seven Republicans on Sunday wrote directly to Tehran to suggest that any nuclear deal with the Obama administration would not be constitutionally binding because a future president or Congress could take steps to revoke it. Biden called the move an unprecedented affront “designed to undercut a sitting president.”

“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 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 released by the White House.

“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,” he added.

The kind of executive agreements to which Biden refers are a consistent feature of U.S. foreign policy important for purposes like basing U.S. troops abroad, protecting those soldiers from prosecution in foreign countries and enabling intelligence and defense cooperation with other governments. They have historically been upheld by U.S. courts.