Arms Export Control Act — The Law Governing US Weapons Sales

The Arms Export Control Act (AECA, 1976) is the primary US statute governing the sale, lease, and transfer of defense articles and services to foreign governments. Under Section 4 (22 U.S.C. § 2753), recipient countries must give 'end-use assurances' — legal commitments that US-supplied weapons will not be used for unauthorized purposes, including offensive operations against civilian populations. The President is required to terminate assistance when these assurances are violated.

The Leahy Law (22 U.S.C. § 2378d) operates alongside the AECA and prohibits US military assistance to foreign security forces 'credibly implicated' in gross human rights violations. Together, the AECA and Leahy Law create a legal framework requiring ongoing monitoring of how US weapons are used. In practice, the executive branch exercises wide discretion in determining whether violations have occurred — and Congress has rarely forced the President's hand.

The AECA became a flashpoint during Israel's 2023–2024 military operations in Gaza. Multiple human rights organizations and members of Congress argued that Israel's use of US weapons — including bombs and artillery in densely populated areas — constituted violations of AECA end-use conditions and potentially the Leahy Law. The Biden administration's National Security Memorandum 20 assessment (May 2024) concluded it was 'reasonable to assess' violations had occurred but stopped short of formal findings that would trigger aid cutoffs — a legally contested outcome.