Transfer of Defense Articles: Sale and Export of U.S.-Made Arms to Foreign Entities [April 30, 2020] [open pdf - 1MB]
From the Summary: "The sale and export of U.S.-origin weapons to foreign countries ('defense articles and defense services,' officially) are governed by an extensive set of laws, regulations, policies, and procedures. Congress has authorized such sales under two laws:  The Foreign Assistance Act (FAA) of 1961, 22 U.S.C. §2151, et seq.;  The Arms Export Control Act (AECA) of 1976, 22 U.S.C. §2751, et seq. The FAA and AECA govern all transfers of U.S.-origin defense articles and services, whether they are commercial sales, government-to-government sales, or security assistance/security cooperation grants (or building partnership capacity programs provided by U.S. military personnel). These measures can be provided by Title 22 (Foreign Relations) or Title 10 (Armed Services) authorities. Arms sold or transferred under these authorities are regulated by the International Traffic in Arms Regulations (ITAR) and the U.S. Munitions List (USML), which are located in Title 22, Parts 120-130 of the Code of Federal Regulations (CFR)."
CRS Report for Congress, R46337
Congressional Research Service: https://crsreports.congress.gov/