What is the name for the principle of US government that permits the legislative branch to pass specific laws to carry out its broadly defined responsibilities?

The principle is known as the "Necessary and Proper Clause," often referred to as the "Elastic Clause." It is found in Article I, Section 8 of the U.S. Constitution and grants Congress the power to make laws that are necessary to execute its enumerated powers effectively. This clause allows for a flexible interpretation of congressional authority, enabling lawmakers to address changing needs and circumstances.