Legal Definitions - affectation doctrine

The Affectation Doctrine, also known as the Effects Doctrine, is a principle in Constitutional law that allows Congress to regulate intrastate activities that have a significant impact on interstate commerce. The name of the doctrine comes from the fact that the test is whether a particular activity "affects" interstate commerce.

For example, if a company in one state is producing a product that is sold in many other states, Congress can regulate that company's activities under the Affectation Doctrine. Similarly, if a state's environmental regulations are causing pollution that affects neighboring states, Congress can regulate those regulations under the Affectation Doctrine.

The Affectation Doctrine is an important tool for Congress to regulate activities that might otherwise fall outside of its jurisdiction. By using this doctrine, Congress can ensure that interstate commerce is not unduly burdened by intrastate activities.