There is no federal law requiring States to enforce federal drug policy. The inability of the federal government to compel state laws has been a source of tension throughout US history.

For a non-controversial, consider the drinking age in the US. To a first approximation, this was set by Congress in 1984 with the National Minimum Drinking Age Act. However, this law doesn't actually set a drinking age. It witholds federal highway funding from states that refuse to do so.

For a more controversial example, consider the medicaid expansion portion of the Affordable Care Act. The Supreme Court ruled that the federal government could not compell states to implement it, allowing some states to not do so. For completeness, I should point out that the expansion was 100% federally funded to start with, and dropped gradually to 90% by 2020, where it is set to remain indefinitely.

Another major example from US history is the Fugitive Slave Act, which required non-slave states to assist in returning escaped slaves. Some Northern states refused to coorporate with this law and was part of what led to the civil war. (Ironically, this is probably the clearest way that "states' rights" was a cause of the civil war, but I don't think it is what most people have in mind when they say "states" rights".

I don’t believe the states have to embrace everything the federal government says - see marijuana and enhanced IDs as examples. However the federal government often ties receiving federal funds to passing and enforcing federal policy. So don’t want to issue identification documents in compliance with the real ID act? Loose a portion of the highway funds. Want legal pot? Loose a portion of the highway funds. And so on.

State law can't override federal law. They have just instructed state police to not enforce that specific law. You could still be convicted by the FBI if they were to get involved for whatever reason, such as selling across state lines.

Interstate trade of marijuana is illegal, even between states that legalized trade inside state borders.

Jurisdiction be jurisdictin'.