In 1945 after the crushing of the Nazi regime by the Allies

In 1945 after the crushing of the Nazi regime by the Allies....

In 1945 after the crushing of the Nazi regime by the Allies, then US President Roosevelt argued against Joseph Stalin and some members of his team that the Nazis should be executed without trial for their atrocities. Roosevelt thought executions without trial was not ideal. This idea that fair hearing was an important part of America’s foreign policy gave birth to the Nuremberg Trials. America’s foreign policy has changed since 1945 especially when dealing with terrorists. Why? What explains this change?