There are two schools of thought. One, based on "original intent" by the Founding Fathers held that the nation was governed strictly by the plain language of the Constitution which limited the power of the federal government to national security and international relations. All other power and authority was left to the several states and to the people, as they greatly feared the inevitable tyranny of democracy. The legislature was to pass laws only within this specific authority and the judiciary was to determine only if such laws did or did not violate the bounds of that authority. Put simply, this established a free society rather than a governing system that had the power to do things for you but also to do things to you in an manifestly unfree society. This didn't sit well with the political class and their special friends since it left them few ways to dispense privilege (or more accurately corruption) and perpetuate themselves in office, so this second view is that the legislature is free to pass virtually any law (based on the interstate commerce provision when in fact the clear intent of that provision applied only to duties levied between states) and the judiciary is free to make any decision they like on virtually any subject they like based on their political leanings. Worse yet, while we slept the political class created a vast unelected, unaccountable bureaucracy that is allowed to make laws (regulations) and oppress the citizenry completely beyond the consent of the governed. Kings would have liked such powers. Be very afraid; the second option is in control and the tyrannical panderfest is afoot. Few people here and abroad understand that this is the problem with Europe and that we are next.
It would be interesting to speculate on how in the computer age we could reform the process to regain our freedom. With the judicial system, forget a Turing test; intelligence is not needed. A fairly simple program could determine if a particular law passed by Congress was in violation of federal authority. Enforcement would be an issue since electric shock to the offending legislators is probably out. I would personally favor cutting them off for the rest of their terms; no more fat paychecks and nobility style perks. That should get their attention since at present most of them have no idea what their Constitutional authority is, or consider it relevant and violate their Oath of Office with impunity.