At the beginning of the 1990s, the Commission saw the European Parliament (EP) as an immature and irresponsible actor lacking appropriate competence on international trade matters. Why then did the Commission become an ardent advocate for extending the EP’s role in trade during the European Convention resulting in a significant increase in the EP’s trade powers? Three potential explanations are investigated: that the Commission saw the EP as a strategic ally, that it wanted to avoid interinstitutional conflict, and that it sought to make EU policy more legitimate. All contribute in accounting for the Commission’s support, but the latter in particular sheds light on both the timing and the form of its change in position. It is suggested that the Commission will emphasise systematic cooperation with the EP when there is external normative pressure, but the article also underscores the extensive pragmatic relations between the EP and the Commission.