In order to effectively write grand strategy for the twenty first century it is important to understand how American exceptionalism among other influences affects U.S. grand strategy. The ideological constant of American exceptionalism has historically influenced and at times constrained U.S. grand strategy. American exceptionalism continues to influence Americas grand strategy in the present and is likely to do so in the future. A historical analysis is used to analyze the historical roots of exceptionalism in the United States starting with the Puritans and other thinkers of the time. The analysis continues to look at how American exceptionalism has evolved with America to include its influence on the quest for independence and the early post revolution grand strategies. This idea of American exceptionalism started to find itself in conflict with the competing ideologies of political idealism and the principles of political realism. This conflict and its effect on grand strategy continue to exist even in the context of todays grand strategy as U.S. grand strategy struggles with the idea of being a non interfering example to other nations and the need to use the spread of American ideas as a way to mask the realist tendencies of what America perceives as its own interests of self security. American exceptionalism continued to influence and at times constrained the grand strategy of the United States throughout different administrations as the country and its grand strategy continued to evolve. This trend of the continuing influence of American exceptionalism continues today in regards to Americas grand strategy.