This thesis is a case study of the post-2020 climate negotiations of the European Union (EU), referred to as the 2030 negotiations. Recent research suggests that the financial crisis and lack of success of global climate negotiations has led to increasing division within the Member States, challenging the EU s ability to create strong climate commitments. The 2030 negotiations were initiated by the European Commission in January 2014, and were finalized when the Heads of Member States found agreement on the 2030 climate and energy package in the EU Council in October 2014. The thesis investigates the negotiating process in light of two countries on opposing sides of the widening interest gap as it asks: how can we understand the influence of Poland and Germany on the 2030 negotiation? The theoretical framework of the analysis is two‐level game theory, established by Robert Putnam in 1988. The theory underscores the importance of domestic interest constellations on the negotiating power of states in international negotiations. In order to capture the interests, power and coalitions among domestic constituents in Poland and Germany an extensive media analysis of 87 news articles has been carried out. Two-level game theory underplays the significance of interstate relationships and dependence, thus alternative theoretical approaches are explored in the case study. Neoliberalism suggests that interstate dependence relations effect the actions of states. In this perspective the imbalance in dependence in the bilateral relationship Poland-Germany should effect the negotiation. Germany is a stronger player than Poland in the EU, being a founding Member State and the largest economy in the Union. Complex interdependence however, points out that in modern democracies, power or ability to influence is issue specific, and does not transfer from one issue to another. The thesis concludes that Germany was a pusher and Poland a dragger in the negotiations. The case study shows that the 2030 climate and energy package was a compromise, an outcome within the interests of both states. Furthermore, trade-offs, issue-linkage as well as side- payments were important mechanisms that allowed for agreement. The value of the two-level game theory was proven, as many of the mechanisms that occurred targeted specific domestic groups to sway them not to oppose the climate package. The issue-specific power concept of complex interdependence theory had merit in the case study, as Poland proved to have the upper hand in the negotiations.