The politics of Vietnam was born in the early Cold War when Republicans made a concerted effort to undercut the national security advantage that Democrats enjoyed after a decisive victory in World War II. The years after the war are often remembered as a period when politics stopped at the water’s edge. Nothing could be further from the truth. Although there were a number of factors that moved the US military deep into the jungles of Vietnam, including a “domino theory” positing that if one country fell to communism everything around it would follow, partisan politics was a driving force behind this disastrous strategy. The same political logic and prowess that led President Lyndon Johnson to strengthen the legislative coalition behind his Great Society simultaneously pushed him into a hawkish posture in Southeast Asia.