Working on public work contracts with any U.S. government agency, including construction and service contracts in connection with national defense or with war activities outside the U.S.
Working on contracts approved and funded by the U.S. under the Foreign Assistance Act, generally providing for cash sale of military equipment, materials, and services to its allies, if the contract is performed outside of the United States
Working for American employers providing welfare or similar services outside of the United States for the benefit of the Armed Forces, e.g. the USO