Joseph Grew (1880-1965) was a senior American diplomat, a career Foreign Service Officer best known for his work with Japan, although he held many senior posts. While culturally knowledgeable, he never learned to speak the Japanese language and may have been overly affected by Japanese policy influencers with Western education.
He was the Minister to Denmark and to Switzerland between 1920 and 1924, returning to Washington as Under Secretary of State, participating in establishing the Foreign Service. Next, he was Ambassador to Turkey from 1927 to 1932.
He became U.S. Ambassador to Japan, presenting his credentials on 14 June 1932. The Seagraves write that his most trusted Japanese contacts were Count Nobuaki Makino, Princess Chibibu's father, Tsuneo Matsudaira, and Ambassador Shigeru Yoshida. All were of the Japanese establishment, and Grew had no significant contacts with Japanese radicals. 
Second Sino-Japanese War
Grew formally protested attacks on American property and flags in the Shanghai-Nanking war zones in China, which then-Foreign Minister Koki Hirota brought to Cabinet attention in mid-January 1938. He reinforced this, in 1939, telling Foreign Miniser Hachiro Arita that no international finance would be available with the instability in China. 
As late as February 1941, he said that "Japan in China has a good case and a strong case if she knew how to present it," but images of brutality reduced international support;  some of the hostility was aggravated by Soviet and Chinese propaganda. 
Days before Pearl Harbor
Cordell Hull, against Grew's advice, gave Nomura a "draft mutual declaration of policy" and a ten-point outline for a comprehensive agreement. It called for Japan to "withdraw all military, naval, air and police forces from China and Indochia," but left "China" undefined. In addition, Hull rejected Henry Stimson's doctrine of nonrecognition and simply did not mention Manchuria. 
With the breaking of diplomatic relations with the start of the war, he left Japan on 25 June 1941.
He again became Under Secretary of State, from 20 December 1944 to 28 July 1945, when he became Secretary of State ad interim when the regular Secretaries were participating in international conferences.
"Grew served as Acting Secretary of State for most of the period from January to August 1945 as Secretaries of State Edward Stettinius and James Byrnes were away at conferences. Among high level officials in the Truman Administration, Grew was the most knowledgeable of Japanese issues, having spent so much time in Japan." He left that post on 3 July 1945.
"Grew was a member of the "Committee of Three," along with Secretary of State Henry Stimson and Secretary of War James Forrestal. This group sought to find an alternative way to make Japan surrender without using atomic bombs. Assistant Secretary of War John McCloy drafted a proposed surrender demand for the Committee of Three, which was incorporated into Article 12 of the Potsdam Declaration. The original language of the Proclamation would have increased the chances for Japanese surrender as it allowed the Japanese government to maintain its emperor as a "constitutional monarchy." Truman, who was influenced by his Secretary of State James Byrnes during the trip by ship to Europe for the Potsdam Conference, changed the language of the surrender demand. Grew knew how important the emperor was to the Japanese people and believed that the condition could have led to Japanese surrender without using the atomic bombs.
Grew stated, "If surrender could have been brought about in May 1945 or even in June or July before the entrance of Soviet Russia into the war and the use of the atomic bomb, the world would have been the gainer.""
- Grew, Joseph Clark, U.S. Department of State
- Sterling Seagrave and Peggy Seagrave (1999), The Yamato Dynasty: the secret history of Japan's imperial family, Broadway Books, ISBN 07677904066, p. 153
- Herbert P. Bix (2001), Hirohito and the making of modern Japan, Harper Perennial, ISBN 978-0060931308, p. 337
- Merion and Susie Harris (1991), Soldiers of the Sun: the Rise and Fall of the Imperial Japanese Army, Random House, p. 255
- Harris & Harris, p. 270
- Harris & Harris, p. 294
- Bix, p. 428
- Harris & Harris, p. 396
- Joseph Grew, Nuclear Age Peace Organization