In this dissertation, I develop and empirically test a comparison of the private versus public strategies presidents use to gain support and passage of their policy agendas. By focusing on presidential influence on policy outcomes in Congress, I can determine which form of presidential leadership - going public or using private bargaining or both - may prove most effective in shaping policies to suit the administration's political interests, given the context in Congress. This allows for an assessment of Neustadt's (1990) classic private bargaining presidency and Kernell's (1997) public presidency to show that both may be compatible and may even work in combination in order for presidents to pass their policy agendas under varying political circumstances in Congress.Original data is collected from Statements of Administration Policy to examine private presidential rhetoric, and additional data is collected from the yearly editions of Congressional Quarterly Almanac to assess the effects of public presidential rhetoric. I test my hypotheses with this new collection of data using logistic regressions, as well as complimentary case studies of No Child Left Behind, immigration reform, and the Andean Trade Preference Act. The broader implications of this study include: systematic assessments of presidential influence on Congress; indentifying a broader view of presidential leadership to better fit empirical observations; and incorporating inter-branch influences in Congressional behavior.