If most of the traditional policy approaches propose a causal and deterministic framework to explain policy change, they fail to clarify how, in the same context and over a brief period, a government can successively take different and contradictory decisions. In order to understand this phenomenon and to better consider the importance of uncertainty in the policy process, this article develops a pragmatist constructivist framework (PCF) to study the indeterminacy of the struggles that unfold within many public and discrete spaces of debate in the politico-bureaucratic world. It also analyzes the unpredictable flows between these different spaces. Developing a pragmatist approach, the article highlights the uncertain conditions of success of several solution proposals by insisting on the importance of the definitional changes adopted by their spokespersons to facilitate the enlistment of new supporters and resist the various tests in the form of critical arguments and power relations. Drawing on a large qualitative study, the PCF relies on the meticulous empirical reconstitution of interactions and scenes of action to understand the complex and unexpected sequence of events that led to a given solution and to propose a specific analysis attentive to the complex relationship between power, knowledge, meaning and ownership struggles.