Using the two short source extracts below about federal drug policy and states legalising recreational cannabis, evaluate the argument that federal power is constrained by state-level policy divergence. Source A: 'The Controlled Substances Act (CSA) remains federal law classifying marijuana as illegal; federal prosecutors retain discretion, but Congress and the Department of Justice can enforce the CSA across all states.' Source B: 'Since the 2010s numerous states have legalised recreational cannabis and implemented state regulatory systems, creating de facto legal markets in conflict with federal law; these states rely on state licensing, taxation and policing rather than federal approval.' Using these sources and your knowledge of US federalism, evaluate the extent to which state policy divergence constrains federal power over drugs.
(Total for Question 10 is 12 marks)