Diplomacy is the best policy
In his "Farewell Address" (1796), first US president George Washington advised future American leaders on how to manage foreign affairs. He advocated the development of commercial relations with foreign countries and the curtailment of political bonds. He observed that the US' "detached and distant situation" enables Americans to pursue a different course. He also advocated against "standing on foreign ground" and against "engaging in permanent alliances with any portion of the foreign world".
Furthermore, he said, interactions "are recommended through policy, humanity and interest", and future leaders should approach them with all nations within the framework of "harmony, open-minded intercourse".
Generally speaking, American leaders have failed to heed Washington's counsel. Since the end of World War II, they have intensified political bonds with foreign countries, stood on foreign ground, and engaged in permanent bilateral and multilateral alliances. Also, they have conducted the majority of their interactions with foreign countries not within the framework of humanity and interest. Instead, their main instrument and organizing principle of US foreign policy have been military. Often this approach has been combined with a nation-building policy through economic means, which harms the political cultures and social fabrics of countries situated far from America's shores.
Significant changes in the US foreign policy could be traced back to the end of World War II. Although the US emerged from the war as the preponderant power, its leaders reached no such conclusion. Perceiving that the rise of the Soviet Union created a precarious balance of power in the international system, the US leaders believed the threat resulting from this unstable balance significantly endangered US national security.
So the leaders restructured the American domestic intelligence and military systems, and adopted new foreign policy approaches underpinned by the threat of force. The National Security Act of 1947 reordered the intelligence community and military, but most importantly, it created a permanent, professional military and placed foreign policy powers within the executive branch.