There are a multitude of influences on presidential decisions to use military force -- pre-tenure life experiences, domestic politics, and so on. The three papers that comprise this dissertation, each formatted as separate journal articles, are linked thematically and interrogate the impact of such variables. The first article, entitled "To Underpin or Undermine? Interbranch Relations and the Use of Military Force," provides an overview of extant literature in the field. Interdisciplinary scholarship provides insight into the influence of interbranch politics on decisions to use military force in the American context. To appreciate this influence, however, requires an understanding of the changing relationship between the executive and legislative branches of government and the impact of public opinion on both branches of government. This review finds that our understanding of these factors is incomplete and requires further study. Interpretations of war powers between the two branches, for example, have evolved from their original conception in the Constitution, creating a perception of a power imbalance between them. Because this view (however valid) raises questions of accountability, further scrutiny of the perceived imbalance is warranted. Equally important, since history demonstrates that politics do not stop at the water's edge, is the influence of public opinion. Manipulated public opinion especially becomes an important, but not well-understood, variable in a complicated give-and-take that involves both branches in their response to, and capacity to shape, public opinion --a dynamic that could be construed as either underpinning or undermining America's democracy. The second article, "Toward an Understanding of American Presidents' Decisions to Use Military Force," builds on the literature that traces life experiences to these decisions, and provides evidence that leader-centric explanations and system-centric explanations are not mutually exclusive. It specifically complements research by Horowitz et al. (2015), who explore the biographical traits that contribute to a world leader's "risk" score -- an index for the narrow choice to enter an interstate conflict. The article identifies the features that drive American presidents' (1945-2000) riskiness and refines Horowitz et al.'s measurement of leader risk. The revised risk scores differ from the assessments of surveyed historians, and an explanation is provided by examining an outlying case, President Jimmy Carter and the Iran hostage crisis. Finally, the third article entitled "The Essence of Reporting: Why Presidents Notify Congress Consistent with The War Powers Resolution (WPR)," takes a closer look at a law designed to constrain a president's ability to use military force and encourage greater coordination between the executive and legislative branches of government regarding the initiation of hostilities. Since its passage in 1973, the WPR appears to have mostly become an administrative notification process that preserves a president's authority to deploy troops for combat for extended periods of time without requiring the type of Congressional consultation originally envisioned in the statute. While this has been well-documented in existing literature, another question is worth exploring: Why are there times when presidents go along with reporting requirements and other times when they do not? Indeed, presidents frequently, but do not always, report to Congress consistent with the WPR's provisions (specifically the 48-hour notification requirement and the 60-day deployment threshold absent subsequent authorization). This article seeks to investigate this inconsistent record to determine what circumstances make presidents more or less likely to comply. To do so, it employs a novel dataset of both WPR-related presidential notifications and non-notifications from 1973-2014. Doing so reveals a key aspect of interbranch politics that underpins decisions to use military force, namely, that presidents appear to abide by the law when the political benefits exceed the political costs.