

If a law can be ignored, its merely a suggestion. If a sub-national jurisdiction could just overrule the national government, then the sub-national government is essentially a sovereign nation.
Think of like the UN and “International Laws”, everyone just ignores those. Anything passed by the UN doesn’t matter. Russia continue to invade Ukraine; Israel continues to genocide Gaza; “UN Resolutions” are just “Strongly Worded Letters”
In these federal system such as the US, federal law is supreme and overrides sub-national laws. Roe V Wade, although it wasn’t technically a law, carried the weight of a law and legalized abortion nationwide. No state could just outright ban abortion, at least not until Dobbs decision reversed the previous Roe decision. Same with Gay Marriage, its now a federal law and states cannot override that.
For those that you could override, say, minimum wage: That you’re technically not overriding. The Federal minimum is still $7.25/hour, a state law making their state $15/hour does not contradict that at all; The federal law did not put a limit on states passing their own laws.