The EU court of Justic has the highest power within the EU, and it requires 2 majorities to agree on something, making Brexit negotiations complex
the UK remaining in the Single market measn the European Court of Justic will still have power within the UK, and the UK will still have to follow their laws
the direct effect legal principle is that laws automatically apply in evert member state, so the UK would still have to follow it to stay in the free market after Brexit
the primacy principle is that if a countries laws contradict EU laws, EU law wins
the Treaty of Rome was made to make the union closer, and transfer sovereignity from National to EU level
Tarriffs are the biggest source of revenue for the EU
spillovers and externalities can be positive or negative, and are better managed by a central power
centralisation is complicated because it means people have less power in choosing who makes their decisions
centralisation reduces the accountability that the decision maker has when local decisions are made
centralised decision making creates juristictional problems, as people cannot leave an area which has a policy that they disagree with as easily
centralisation creates scale economies of decision making, with it being cheaper to aquire information, and implement one broad policy over many individual ones