AbstractThis paper investigates time variations in the implementation of legislative requests by the Swiss government. Combining the literature on executive–legislative relations with findings from implementation research, we focus on the procedural level and argue that implementation delays can occur because the government does not want to, cannot or should not implement faster. We test these mechanisms using a unique database, which enables us to analyse a systematic collection of all legislative requests that have been approved between the parliament’s 2003 winter session and its 2018 spring session. Our results show that the considerable variation in the time needed for the legislative mandates’ implementation is mostly related to the Swiss government’s inability to transpose faster, i.e. to factors like highly busy administrative offices or complex and controversial issues. In contrast, there is no support for the ideas that the government “shall not” or “does not want to” transpose faster.