Groupthink in US foreign policy

US foreign policy's feature is the power and experiences of the interventions for resolve other country's conflict and tyranny. For the explanations of US foreign policy, especially on the intervention, I think the "Groupthink" model is the most useful approach.
　The "too many ways of explaining policy" reflected such as too many stakeholder, ideology, perception of the foreign policy in America. Without examined the final decision makers, we cannot explain effectively. Foreign policy such as intervention is always tough judge, and this should be done the President who is the person in all accounts. Of course, ideology and international structure are the very important reasons of the judge. However, these are situations and causes of decision, not the actions exactly.
　For example, Vietnam war had its origin in intervention, because of the anticommunism. But, President Johnson once get the resolution for intervention against Tonkin Gulf Resolution, the president overstepped the rights to use forces, and the war dragged on endlessly.
　The least useful approach is "business interests" model. First, it is difficult for the decision of foreign policy, especially intervention, because of only business interests. This is also significant for the cost-benefit analysis of Vietnam War, Kosovo intervention, etc. Second, this is crucial that the company who earned from war or intervention unconcealed cannot run the business on the opposition of stockholders and customers. In short, the company may earn, but the multinational big companies are unwilling to business with such company. Furthermore, the compliance has become crucial norm, such as SOX (Sarbanes-Oxley Act), the business on the war has gotten more and more difficult. Then, foreign policy based on business interest doesn't pay.