This dissertation identifies and explains the factors contributing to the presence and severity of U.S. foreign-policy blunders, or gross errors in strategic judgment resulting in significant harm to the national interest, since the Second World War. It hypothesizes that the grand strategy of preponderance and the overestimation of military power to transform the politics of other states have precipitated U.S. foreign-policy blunders since 1945. Examining the Vietnam War and Iraq War as case studies, it focuses on underlying conditions in the American national identity and the problematic foreign policy decision-making (FPDM) that corresponds to this bifurcated hypothesis, termed the overestimation/preponderance theoretical model (OPM). Four indicators operationalize the OPM: (1) how U.S. foreign policymakers estimated the capacity of military power to transform the political dynamics of the target state through intervention; (2) and (3) how U.S. actors and institutions affected the capacity of the partner state and hostile state and nonstate actors; and (4) how the foreign policy was justified and rationalized within the leadership of government and to the general public as it encountered disconfirming information.
In each case, the grand strategy of preponderance instituted a bounded rationality of mission in the FPDM stage and the operationalization stage that precluded the inclusion of an unfavorable outcome. In each case, U.S. foreign policymakers greatly overestimated the capacity of the partner state to establish security and legitimacy and underestimated the capacity of hostile actors to mobilize and threaten the partner state. However, these preference-confirmation biases diametrically contradicted the assessment that victory would be easy to achieve; U.S. foreign policymakers promulgated this corresponding overestimation/underestimation even while inflating the threat far beyond what the actual threat to the national-security element of the national interest represented. The subsequent implementing of this inverted calculation created a national-security national interest where none was extant, then significantly harmed that new interest via intervention. This tactical application of the grand strategy of preponderance facilitated the strategic-tactical gap in U.S. foreign policy by creating monsters in order to have monsters to slay, consistent with the ideological tradition of the imperative of crusade in the modern history of American foreign relations
