Final answer:
The U.S. Constitution grants Congress the power to regulate interstate and international commerce mainly through the Commerce Clause. This authority has been broadly interpreted since the 1930s to allow federal regulation over various economic activities and has impacted areas like civil rights and environmental laws. The commerce clause provides a unified national market by preventing states from imposing taxes or tariffs on goods from other states.
Step-by-step explanation:
Regarding the regulation of interstate and international commerce, the U.S. Constitution grants Congress the authority to create laws that govern commercial interactions between states, and between nations and states. This power is derived from the Commerce Clause found in Article I, Section 8, Clause 3 of the Constitution. Initially, the clause was interpreted narrowly, limiting Congress's regulatory reach. However, beginning in the 1930s, and especially during the New Deal era, the interpretation broadened significantly and resulted in Congress exercising a much wider regulatory power over economic activities that affect interstate commerce.
This broad interpretation has allowed the federal government to regulate a variety of issues that traditionally fell under state jurisdiction, such as labor standards (e.g., setting a national minimum wage), drug laws, and environmental protections. The influence of the commerce clause also led to congressional action in civil rights legislation, aimed at ending racial segregation. It's important to note though, that the commerce clause does not grant Congress unlimited power. The Supreme Court has, from time to time, limited Congress's authority under the commerce clause to ensure that states’ rights are not unduly infringed upon.
States are not allowed to levy taxes or tariffs on imports from other states, as detailed in Section 10 Clause 2 of the U.S. Constitution. This is because only the federal government holds the power to regulate interstate trade, ensuring a unified economic system without internal barriers to trade, reflective of a single national market rather than a collection of independent state economies.