The U.S. Constitution requires a two-thirds Senate majority to ratify formal treaties with foreign nations (Article II, Section 2). However, presidents can also make executive agreements with foreign governments that don't require Senate ratification. Executive agreements are used for a wide range of international commitments, from trade arrangements to diplomatic understandings. The JCPOA was structured as an executive agreement rather than a treaty, allowing Obama to conclude it without a Senate vote — but also allowing Trump to withdraw from it without one. The Iran Nuclear Agreement Review Act of 2015 gave Congress the right to review the JCPOA and vote to disapprove it within 60 days, but Congress didn't do so. This means the JCPOA's terms have no statutory force in U.S. law, unlike formal treaties, which are the "law of the land" under Article VI.