What explains the outcome of interstate negotiations in international organizations (IOs)? While existing research highlights member states' power, preference intensity, and the IO's institutional design, this paper introduces an additional source of bargaining power in IOs: Through issue linkage members of an IO leverage privileged positions in other IOs to obtain more favorable bargaining outcomes. Specifically, European Union members are more successful in bargaining over the EU budget while they hold a non-permanent seat on the United Nations Security Council (UNSC). Inside the UNSC EU members can promote security interests of other European countries, and they can use their influence to secure side-payments from the EU budget. The study tests this argument by investigating new EU budget data, and it shows that EU members obtain 1.7 billion Euro in additional net receipts during a two-year UNSC term, on average. Thus, bargaining processes in the EU and the UN are intricately linked.
