He protested the Japanese invasion of Manchuria, which instituted the Stimson Doctrine of nonrecognition of international territorial changes that are executed by force.

After the U.S. entered the war, Stimson, working very closely with Army Chief of Staff George C. Marshall, took charge of raising and training 13 million soldiers and airmen, supervised the spending of a third of the nation's GDP on the Army and the Air Forces, helped formulate military strategy, and oversaw the Manhattan Project to build the first atomic bombs.

[4] He was educated at Phillips Academy in Andover, Massachusetts, where he gained a lifelong interest in religion and a close relationship with the school.

[5] He was an honorary lifetime member of Theodore Roosevelt's Boone and Crockett Club, North America's first wildlife conservation organization.

Stimson continued the reorganization of the army that had begun by Elihu Root, which improved its efficiency prior to its vast expansion in World War I.

After the U.S. declared war on the German Empire in April 1917, Stimson was one of the 18 men selected by former President Theodore Roosevelt to raise a volunteer infantry division for service in France in 1917.

Stimson subsequently served in the regular U.S. Army in France as an artillery officer and reached the rank of colonel in August 1918.

The choice of Stimson, a conservative Republican (and anti-New Dealer) and Frank Knox as secretary of the Navy was a calculated effort by the president to win bipartisan support for what was considered the almost-inevitable U.S. entrance into the war.

In the seventeen months leading up to the Japanese attack on Pearl Harbor, Stimson, working side-by-side with U.S. Army Chief of Staff George C. Marshall (in offices adjacent to one another where the door between them was deliberately left open at all times) led efforts to prepare an unprepared America for war.

[23] Because of this view, when the Senate voted to confirm him, all of the most notorious isolationist Senators such as Henrik Shipstead and Ernest Lundeen of Minnesota, Gerald Nye of North Dakota, Robert Marion La Follette of Wisconsin, David I. Walsh of Massachusetts and Burton K. Wheeler of Montana voted against his confirmation on the grounds he was "too pro-British" whereas all of the most "Anglophile" Senators such as John H. Bankhead II and J. Lister Hill of Alabama, Kenneth McKellar and Tom Stewart of Tennessee, Harry Schwartz and Joseph C. O'Mahoney of Wyoming all spoke in favor of Stimson and his foreign policy views (and voted to confirm him as Secretary of War).

"[26] The power of isolationists explains why Stimson did not record "shock, horror or anger" after Roosevelt informed him of the attack on Pearl Harbor.

"[27] During the war, Stimson oversaw a great expansion of the military, including drafting and training of 13 million soldiers and airmen as well as purchasing and transporting 30 percent of the nation's industrial output to the battlefields.

"[31] Stimson was initially opposed to the internment of Japanese Americans away from the West Coast, but he eventually gave in to pro-exclusion military advisers and secured Roosevelt's final approval for the incarceration program.

Still opposed to the idea of wholesale eviction, Stimson spent much of January 1942 in fielding calls from military advisers and West Coast politicians on the potential threat of a Japanese American fifth column.

On February 11, Stimson and McCloy briefed in a phone conference Roosevelt, who gave his Secretary of War the go-ahead to pursue whatever course he saw fit.

[32] As the Western Defense Command began circulating civilian exclusion orders, a new debate formed regarding Japanese Americans in the Territory of Hawaii.

"[34] Stimson authorized the release of Japanese Americans from camp in May 1944 but postponed permission for them to return to the West Coast until after the November elections to avoid controversy in Roosevelt's upcoming campaign.

Explaining his opposition to the plan, Stimson insisted to Roosevelt that 10 European countries, including Russia, depended upon German trade and its production of raw materials.

He also stated that it was inconceivable that the "gift of nature," which was populated by peoples of "energy, vigor, and progressiveness," should be turned into a "ghost territory" or "dust heap."

What Stimson most feared, however, was that a subsistence-level economy would turn the anger of Germans against the Allies and thereby "obscure the guilt of the Nazis and the viciousness of their doctrines and their acts."

[39] Stimson, a lawyer, insisted, against the initial wishes of both Roosevelt and British Prime Minister Winston Churchill, on proper judicial proceedings against leading war criminals.

The original target list included the city of Kyoto, a place of immense cultural and historical significance to the Japanese people.

[43][44] In his personal diary, Stimson recorded his concern that annihilating such an important cultural site could generate long-lasting hostility among the Japanese people.

He again reiterated with the utmost emphasis his own concurrence on that subject, and he was particularly emphatic in agreeing with my suggestion that if elimination was not done, the bitterness which would be caused by such a wanton act might make it impossible during the long post-war period to reconcile the Japanese to us....[45]The Manhattan Project was managed by Major General Groves (Corps of Engineers) with a staff of reservists and many thousands of civilian scientists and engineers.

Stimson secured the necessary money and approval from Roosevelt and from Congress, ensured that Manhattan had the highest priorities, and controlled all plans for the use of the bomb.

[46] Stimson ultimately concluded if the U.S. had guaranteed the Japanese preservation of the imperial constitutional monarchy, Japan might have surrendered and prevented the use of atomic bombs.

[52] The impact of the atomic bomb, he thought, would go far beyond military concerns to encompass diplomacy, world affairs, business, economics, and science.

"[54][55] To this end, Stimson advocated collaboration with the Soviet Union and genuine international control of atomic technology and weaponry, including possibly turning them over to the United Nations.

Hiroshima and Nagasaki had both contained combatant bases and major centers of war industry that employed tens of thousands of civilians.

Involved were the simple issue of ending a horrible war and the more subtle and more important question of the possibility of genuine peace among nations.