What governmental level primarily enacted changes in the Revenue Act of 1964?

The Revenue Act of 1964 was a significant piece of legislation enacted at the federal level in the United States. This act primarily aimed to reduce income tax rates for individuals and corporations, promote economic growth, and increase consumer spending. The federal government had the authority to implement such tax reforms, as taxes are primarily a matter of federal law and policy, reflecting the national economic strategies of the time. The act was part of President Lyndon B. Johnson's broader Great Society program, aimed at addressing poverty and promoting social welfare.

In contrast, state and local governments do not have the jurisdiction to enact or modify federal tax policies, as these are under the purview of the federal government. Furthermore, international bodies do not hold authority over domestic economic legislation in relation to U.S. tax laws. Therefore, the correct answer accurately reflects the governmental level responsible for enacting the changes brought about by the Revenue Act of 1964.