The European Union (EU) is the largest economic partner of Australia: the EU is Australia's second largest trading partner and the EU is Australia's largest investment partner. Yet, the EU remains the only major trading and investment partner with whom Australia does not have an Economic Integration Agreement or even a Preferential Trade Agreement, either in force or under negotiation. Without one, the legal and policy systems that regulate trade and investment between Australia and the EU must function in the complexity of different levels of political economy: non-unitary internal and external market constitutions against bilateral sectoral and multilateral general agreements on trade and investment.