The Iran nuclear deal is a treaty. From Merriam-Webster.com: “Treaty – an official agreement that is made between two or more countries or groups.” Since this is “an agreement made between two or more countries,” by definition, it is a treaty. According to the Constitution, treaties require approval by the Senate by a two-thirds majority vote. The Iran Nuclear Agreement Review Act turns this on its head. However, the Constitution still applies because the Iran Nuclear Agreement Review Act did not amend the Constitution. If this deal is not approved by a two-thirds vote of the Senate, legally, it will not have been ratified.