John Lewis Gaddis — American Historian

John Lewis Gaddis is the Robert A. Lovett Professor of Military and Naval History at Yale University. He is best known for his work on the Cold War and grand strategy, and has been hailed as the "Dean of Cold War Historians" by The New York Times. Gaddis is also the official biographer of the seminal 20th-century American statesman George F. Kennan.George F. Kennan: An American Life, his biography of Kennan, won the 2012 Pulitzer Prize for Biography or Autobiography... (wikipedia)

The United States came out of the 1990s, if anything, in an even greater position of hegemony and preeminence than it was at the beginning of the 1990s.
I don't think there is necessarily a contradiction between being a hegemonic power on the one hand and functioning multilaterally on the other.
I think the way to think about the impact of Hiroshima is to think about it as a sudden shift in the balance of power.
Second terms in the White House open the way for second thoughts.
The doctrine of preemption has a long and distinguished history in the history of American foreign policy.