system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If states like CO and others can legalize marijuana outside of the federal approval, why can't states like MS or AL outlaw abortions in the same way?

I don't fully understand how the states were able to navigate the federal ban, but from a layman's perspective - if some states can figure out how to navigate the federal laws to get what THEY want, couldn't other states do the same?
(Note: let's not let this devolve into a political fight, I'm curious about the actual legality and not whether one or the other is 'right')
gpt
Colorado and Washington are not so much legalizing marijuana as removing state laws that make it illegal.  States aren't required to enforce federal laws, and in many cases, like immigration, are discouraged from doing so.  Marijuana remains illegal on the federal level, but the feds lack the resources and the inclination to go after state level operations.

Abortion is legal, not due to federal law, but a supreme court ruling on the constitution, that covers all federal, state, and municipal laws.  Any law passed contrary to this is unconstitutional.