A theory of the conditional influence of the European Parliament in the cooperation procedure

I provide a public choice-based explanation of why the European Parliament is sometimes influential in the cooperation procedure. While a conservative Parliament can use its right of rejections to block a decision effectively whenever there is no consent in the Council, a Parliament in favor of change can successfully use its amendment right in the second reading whenever the constraints have been changed unexpectedly since the adoption of the common position such as to create an amendment win set. Then, the European Parliament can choose its most preferred policy in this set which is supported by the Commission, cannot be changed by the Council and is preferred against the status quo by a qualified majority in the Council.