This paper will combine and apply insights from Historical Institutionalism and Discursive Institutionalism to answer this question. It will show that despite the policy continuity, there has been a significant change in the policy ideas underlying and legitimating this policy. One and the same policy has been rejustified through other means over the span of the last 25 years. While Historical Institutionalist concepts of layering and conversion explain part of the story, I will make the claim that the analysis of ideas is necessary to fully understand the continuity in policy and change in underlying policy ideas and legitimation. Applying a Discursive Institutionalist approach enables analyzing how actors arrive at new interpretations of existing institutions and policies and how the discursive interactions between policy agents – constrained and enabled by existing policy-making institutions – result in one policy choice being made over another. This paper moreover seeks to provide further insights in the scope conditions for when ideational factors are more or less likely to explain policy stasis and policy change.