The Development of the Schengen Acquis

This chapter describes the historical genesis of Schengen law, starting from the moment at which the abolition of internal border checks had become a realistic policy option at European level in the 1970s and 1980s. It describes the work that took place on two parallel tracks until 1999, namely the failed attempts to abolish internal border control at EC/EU level and the simultaneously emerging successful intergovernmental cooperation of a smaller group of Member States within the Schengen frame. In 1999, the Schengen acquis, as it existed at that moment, was integrated into Union law, based on the Schengen Protocol and two implementing Council Decisions (the Schengen Acquis Determination Decision 1999/435/EC and the Ventilation Decision 1999/436/EC). From 1999 onwards, the scope of the Schengen acquis should have remained static, due to the Schengen Protocol and the Denmark Protocol as well as the Schengen Association Agreements, which all foresaw a “freezing” of the subject matters considered as Schengen-related as they were in 1999 or upon conclusion of the Association Agreements. However, in practice, this was not always the case, thanks to a restrictive approach taken by the EU/EC legislator from 1999 onwards, when it came to defining the Schengen-relatedness of further developments of the Justice and Home Affairs acquis on subject matters, such as police and judicial cooperation, which had been considered as Schengen related when integrating the Schengen acquis into Union law.