Ascending to the presidency in the midst of a severe economic crisis and an ongoing war on terrorism, Barack Obama faced numerous political and policy challenges. We examine the responsibilities he faced in assuming the received tasks of modern presidential leadership amid a polarized political system. To a point, Obama has embraced partisan leadership, indeed, even further articulating developments in the relationship between the president and parties that Ronald Reagan had first initiated, and George W. Bush built upon. Thus Obama has advanced an executive-centered party system that relies on presidential candidates and presidents to pronounce party doctrine, raise campaign funds, mobilize grassroots support, and campaign on behalf of their partisan brethren. Just as Reagan and Bush used their powers in ways that bolstered their parties, so Obama's exertions have strengthened the Democratic Party's capacity to mobilize voters and to advance programmatic objectives. At the same time, presidential partisanship threatens to relegate collective responsibility to executive aggrandizement. Seeking to avoid the pitfalls that undermined the Bush presidency, Obama has been more ambivalent about uniting partisanship and executive power. Only time will tell whether this ambiguity proves to be effective statecraft—enshrining his charisma in an enduring record of achievement and a new Democratic majority—or whether it marks a new stage in the development of executive dominion that subordinates party building to the cult of personality.