Police powers allow states to: regulate interstate commerce. regulate only public activities, such as protest marches. regulate private activities to promote public health, safety, and general welfare. have state police forces but not exercise any other powers. When a state law comes into direct conflict with a federal law: the state law takes precedence. the federal law takes precedence. both laws apply equally at the same time. both laws are ruled invalid. The first ten amendments to the U.S. Constitution are known as: the Declaration of Man's Rights. the Bill of Rights. the Bill of Rejoinder. the Magna Carta