This article dissects the sources of partisan bias in the institutional structure of the U.S. electoral college. Conventional wisdom and results of recent presidential elections suggest that the electoral college is biased in favor of the Republican Party. While previous empirical studies have challenged this conventional wisdom, George Bush's 2000 electoral college victory revived this debate. Our research provides a direct analysis of the multiple sources of bias within the electoral college and examines their individual impact on each party's electoral fortunes over the last eleven elections (1964-2004) with particular attention on the 2000 and 2004 presidential elections. Our results are in line with previous analyses indicating no significant bias within the electoral college. We conclude that parties and their presidential candidates are rational political actors who utilize sophisticated campaign strategies which allow them to efficiently employ their resources and limit any institutional disadvantages they may face.