The Buy American Act (BAA - 41 U.S.C. §§ 10a–10d) passed in 1933 by Congress and signed by President Roosevelt, required the United States government to prefer U.S.-made products in its purchases. Other pieces of Federal legislation extend similar requirements to third-party purchases that utilize Federal funds, such as highway and transit programs.
President Obama has the power to force this Act, without the approval of congress. it is already a law.