The government DOES regulate drugs (FDA, DEA) and immigration INS, DHS).
That's why most drugs and most residents are legal or illegal.
The states have rights and that is good. However, the Federal government can and does establish basic guidelines. It has moved very slowly, tectonically one might say. Some states are way ahead of the Federal Government and some are way behind.
"We all of us know down here that politics is a tough game. And I don't think there's any point in being Irish if you don't know that the world is going to break your heart eventually."-Daniel Patrick Moynihan, December 5, 1963