Trust in Swiss politics is declining, with a significant share of the population perceiving politicians as diconnected from the people they represent. Concerns about political honesty and the influence of lobbyists further underscore the widening gap between citizens and decision-makers. This paper investigates these concerns in the context of Switzerland’s legislative process, using the CO2 Act and the Climate and Innovation Act as case studies. These laws are particularly relevant due to their social significance and emotionally charged nature, as climate policies impact individuals, businesses, and organisations alike. By synthesising legal and political analysis with economic theories, this paper applies public choice theory—grounded in rational decision-making—and behavioural economics, which incorporates psychological biases, to explain legislative outcomes. After outlining the federal legislative process in Switzerland, with particular emphasis on the completely revised CO2 Act and the Climate and Innovation Act (1.), the analysis explores how self-interest and cognitive distortions influence political decision-making. It then introduces the theoretical foundations of public choice theory and behavioural economics (2.) and applies these perspectives to the Swiss legislative process (3.). Building on this assessment of the existing framework de lege lata, the economic theory of the constitution is subsequently used to identify necessary adjustments de lege ferenda aimed at strengthening the legal framework and curbing self-interested and cognitively distorted behaviour. This interdisciplinary approach provides a deeper understanding of Swiss legislative mechanisms and contributes to the broader debate on governance and public trust.