What most people don't get (even in the USA) is that the constitution doesn't grant powers to people. It only restricts the government from acting on the people. People were born with the right to speak freely and defend themselves as they see fit - the government can't change that for example.

So the 10th says if it isn't mentioned it is a power that belongs to the people or the states. For example, weed isn't mentioned in the constitution so technically it's a 10th issue for states to decide - HOWEVER - this is thing called the commerce clause...

Commerce clause means that if something moves from state to state, that sure does seem like a Federal matter. So it gets complicated. But... In the end, some states have legalized in the state in part referring to 10A, it's their right to do - but if you are in a "weed state" and light up at a DEA office - expect to be arrested and charged with a federal crime.

* The thing about commerce clause is that almost everything can move from state to state. So that's a little bit of an annoying topic depending on the issue and which side you're on. For example, I can manufacture a gun in my state that isn't legal in another state, commerce clause has been tried to limit 2A.