As the preceding chapters indicate, two broad dynamics were at work in American state making after 1945, one associated with an older political culture and the other with the new ideology of national security. Elements of each dynamic could exist side by side in the same individual, pulling in this direction at one time and in that direction at another. Truman and Forrestal were good examples of this tension, as was Taft, whose thinking on international matters changed considerably in the years after Pearl Harbor. Both dynamics could also be present in the same political party, though each was more likely to be identified with one of the major parties than with the other, and with the views and constituencies associated with that party. One was identified with the Democratic party, the other with the Republican party; one was associated with the executive branch, the other with the legislative branch; one was more liberal, the other more conservative; one was internationally oriented, the other tended toward nationalism, regionalism, or even isolationism.

The tension between these two dynamics tapped into a long history of political controversy over the role of the state in American life, and the role of the United States in world affairs.