The necessity of collective decision-making preceded by group discussions in democratic state institutions prompts a reflection upon the quality of this process and its outcomes. The article presents briefly two theoretical models of a debate: Amy Gutman and Denis Thompson's concept of deliberation (based on the works of John Rawls) and Jurgen Habermas' theory of discourse. The authoress analyses the implementation of the principles of those models, taking as an example an ordinary Sejm debate. Then, she attempts to answer the question: why many debates in the real world often fail to lead to a consensus or to an innovatory solution (that would involve a change of the participants' initial convictions and preferences). She suggests a few organizational improvements conducive to a more constructive discussion that would better implement the recommendations of the theoretical models.