sentences:  The Commissioner heads up the Directorate-General for Trade in defining the commercial policy of the EU, which has been exclusively under the EU's mandate since the EEC's Rome Treaty in 1957.Due to the size of the European economy, being the world's largest market and having a huge slice of world trade, this position can be very important in dealing with other world economic powers such as China or the United States.Former Commissioner Leon Brittan commented that “Frankly, it is more important than most [national] cabinet jobs”.