The federal government doesn't have a general police power to pass laws that are useful and good for the health, safety, and general welfare of the citizens.
States have that power.
The feds (Congress) are limited to some enumerated powers, and whatever powers are necessary and naturally inferred to carry out those enumerated powers.
So then, are these "knife rights' bills" in Congress based directly on the Second Amendment?
Or are they based on the "commerce clause" as it relates to interstate transport of items that have been made and distributed in interstate commerce, or are actually being moved in interstate commerce?
What other constitutional basis is there for feds to preempt states' traditional powers when it comes to criminal law?