Which clause allows the federal?

It seems your question got cut off. However, if you are referring to the clause that allows the federal government to take certain actions, you might be thinking of the Necessary and Proper Clause. This clause, found in Article I, Section 8 of the U.S. Constitution, grants Congress the power to make laws that are necessary and proper for carrying out its enumerated powers. This clause enables flexibility in federal legislation and has been the basis for many significant laws and actions.