First, do you mean the Buy American Act of 1933 that requires government purchased products and materials be American in origin, with some stated exceptions such as those related to trade agreements? Or do you mean the Buy America Act of 1983 (50 years later) that pertains to the Department of Transportation and regulates that the "steel, cement, and manufactured products" used in highway projects be "produced in the United States."
Since these acts are related to government agencies procuring supplies and products for government projects:
Buy America applies solely to grants issued by the Federal Transit Administration and Federal Highway Administration; Buy American may be applied to all direct U.S. federal procurement.
if the government were to suspend its preference for domestic products, thousands or hundreds of thousands of American jobs and businesses would be negatively effected. Governments traditionally determine it to be sound domestic policy to support one's own country's labor and product markets, and this strategy is a logical, conservative (as opposed to risky), and sensible one.
Buy American Act 1933
(a) The Buy American Act—
(1) Restricts the purchase of supplies, that are not domestic end products, for use within the United States. A foreign end product may be purchased if the contracting officer determines that the price of the lowest domestic offer is unreasonable or if another exception applies (see Subpart 25.1);
Buy America Act 1983
provides with exceptions that funds authorized for Federal-aid highway projects may not be obligated unless the steel, cement, and manufactured products used in such projects are produced in the United States.