The necessity of forming coalitions is inevitable in a large, diverse nation in which political power is fragmented both vertically and horizontally. Presidents invest substantial time and effort building supporting coalitions for themselves and their polices among the public and within Congress. The author explores the president's ability to build coalitions, examines the relationship between the institutional presidency and obstacles to coalition building, and inquires whether the presidency as an institution is adequate to the task of building the coalitions necessary for governing. He concludes that (1) the president has great difficulty building coalitions for governing among the public and within Congress, (2) the institutional structure of the presidency (and Congress) is at the core of the difficulty of building coalitions in Congress but does not inhibit obtaining public support, and (3) the changes required to notably improve presidential coalition building are so fundamental that they are unlikely to occur.