Truman relieved General MacArthur of his command over coalition forces in Korea in large part because he planned and aggressively advocated the use of nuclear weapons against the Chinese.
If you visit the Princeton stacks, you can unearth many Woodrow Wilson School theses advocating the aggressive use of nuclear weapons during Vietnam. Some of the people who authored these papers went on to craft US trade policy from the 1980s through the present. A truly remarkable change of heart.