Secrecy still characterizes negotiations in the intergovernmental legislative body of the European Union, the Council of Ministers. Even close observers do not know which power resources lead to bargaining success. I distinguish between exogenous and endogenous forms of power. Whereas the former source of influence remains stable during the bargaining process, negotiators can manipulate the second form of power. With two new data sets, the analysis shows that 'exogenous' resources, such as votes and economic strength, lead to success only in certain policy fields; 'endogenous' resources, such as the extremity of a position on a policy dimension and the proximity to the agenda-setting European Commission, are more helpful in predicting bargaining success. Individual negotiating qualities such as negotiating skill and information are less essential than the prescriptive negotiation literature and anecdotes would have us believe.
