But there are limits to the effectiveness of nation
al action. Gaps are left which only the EU can fill. In order to reach its objectives, from the very outset the Treaty assigned a central role to fully-fledged common policies such as competition, trade, transport, agriculture and fisheries, and more recently EMU. There cannot be a true internal market
and a customs union without precise rules to establish a level playing field. Without harmonising the great diversity of Member State policies, internal border controls would have had t
...[+++]o be maintained, the EU could not have spoken with one voice in international trade and sustainability would have suffered in a downward spiral of negative competition.