The anti-commandeering doctrine ensures political transparency—ensures the states isn't acting solely at the discretion of the federal government (federalism).
Ensuring the federal government isn't acting behind a curtain of state action
The federal government cannot force or prohibit a state from enacting legislation.
Limitation: existing federal law is supreme in cases of conflict with state law.
Summation; federal statutes cannot regulate state governments' regulation of their citizens
E.g., Congress cannot tell a state that they cannot repeal a law.