In the early post-war period of the Red Scare, accusations against many American orientalists at the time, such as Knight Biggerstaff, John Paton Davies and E. Herbert Norman, of being agents of influence of the Soviet Union were not infrequent. On the basis of an accusation by the Senate Republican William Fife Knowland in 1949, U.S. Senator Joseph McCarthy accused Lattimore in particular of being 'a top Russian spy'. Some people credit Lattimore with coining the term McCarthyism, but Herbert Block was first to use the term, in a cartoon in the Washington Post. Suspicions aroused by the accusation, though never proven, put an end to Lattimore's career as a key consultant of the United States State Department in Far Eastern affairs.
Although born in America, Lattimore was raised in Tianjin, China, where his parents, David and Margaret Lattimore, were teachers of English at a Chinese university. (His brother was the classics translator Richmond Lattimore. One of his sisters was the children's author Eleanor Frances Lattimore.) He left China at the age of twelve and attended schools in Switzerland and England, but returned in 1919 when it turned out that he would not have enough funds for attending university. He worked first for a newspaper, and then for a British import/export related business. This gave him the opportunity to travel extensively in China. His travels also laid the ground for his life-long interest in all matters related to the Mongols and other peoples of the Silk Road, and for his later reputation as expert on these areas. For his honeymoon he traveled overland from Beijing to Delhi, a mammoth feat in the first half of the 20th century.
Upon his return to America in 1928, he succeeded in receiving a fellowship at Harvard and spent the academic year 1928/1929 as a student at Harvard University. He then was able to return to China under a series of fellowships. In 1937 he became a political adviser to Chiang Kai Shek, and later became acquainted with Zhou Enlai.
From 1938 to 1950, Lattimore was the director of the Walter Hines Page School of International Relations at Johns Hopkins University. He continued to lecture there until 1963. During the 1930s, Lattimore sat on the board of the Institute of Pacific Relations (IPR) and edited the IPR’s journal Pacific Affairs. As editor of Pacific Affairs, Lattimore sought articles from a wide range of perspectives and made the journal a forum for new ideas, especially from the social sciences and social philosophy. Scholars and writers of all persuasions published work, ranging from Pearl S. Buck to Chinese literary figures to hard core Marxists.
Lattimore later came under fire for portraying the Soviet Union in a favorable light. One colleague recalled a letter in which Lattimore justified Stalin's Great Purge, writing, "That sounds to me like democracy. Lattimore congratulated Carter: "I think that you are pretty cagey in turning over so much of the China section of the inquiry to Asiaticus, Han-seng and Chi. They will bring out the absolutely essential radical aspects, but can be depended on to do it with the right touch.... “Asiaticus” was the Polish-born Comintern agent Moses Wolf Grzyb, alias M. G. Shippe (or Schiffe), alias Hans (or Heinz) Muëller (or Moëller); “Han-seng” refers to Chen Han-seng, a member of Richard Sorge’s Soviet spy ring in Tokyo; and “Chi” was Communist Chinese secret agent Chi Chao-ting. In 1938 Lattimore he wrote to IPR General Secretary Edward C. Carter: "For the U.S.S.R. —- back their international policy in general, but without using their slogans and above all without giving them or anybody else an impression of 'subservience.' In response to Soviet complaints that a Pacific Affairs article by William Henry Chamberlin was critical of Stalin, Lattimore replied on a trip to Moscow 'that he had not realized Chamberlin’s position, but as soon as he learned of the Soviet opinion of Chamberlin he canceled an article on the Soviet press which he had asked from Chamberlin.' Lattimore also said that "if the Soviet group would show in their articles a general line—a struggle for peace—the other articles would naturally gravitate to that line. He added that "If the Soviet group would start on such a line, he would be able to make [other councils] cooperate more fully.
Following the German invasion of the Soviet Union in June 1941, President Franklin D. Roosevelt appointed Lattimore U.S. advisor to Chinese Nationalist leader Chiang Kai-shek. In 1944, Lattimore was placed in charge of the Pacific area for the Office of War Information. . At President Roosevelt's request, he accompanied US Vice-President Henry Wallace on a mission to China and Mongolia in 1944, for the US Office of War Information. The trip had been arranged by Lauchlin Currie, who recommended to FDR that Lattimore accompany Wallace. During this visit, which overlapped the D-Day landings, Wallace and his delegation stopped over in Siberia and were given a Potemkin village tour of the Soviet Union’s Magadan concentration camp at Kolyma. In a travelogue for National Geographic, Lattimore described what little he saw of this vast Siberian gulag as a combination of the Hudson's Bay Company and the TVA, remarking on how strong and well-fed the inmates were and ascribing to camp commandant Feliks Nikishov 'a trained and sensitive interest in art and music and also a deep sense of civic responsibility'.. In a letter written to the New Statesman in 1968, Lattimore justified himself by arguing his role had not been that of 'snoop(ing) on his hosts.
During the 1940s, Lattimore came into increasing conflict with another member of the IPR's board, Alfred Kohlberg, who accused Lattimore of being hostile to and biased against Chiang Kai-Shek (who was Kohlberg's hero) and in addition, too left-wing and sympathetic towards Chinese Communists. In 1944, relations between Kohlberg and Lattimore became so bad that Kohlberg left the I.P.R, and founded a journal Plain Talk intended to rebut the claims made in Pacific Affairs. By the late 1940s, Lattimore had become a particular target of Kohlberg and other members of the China Lobby. Kohlberg was later to became an advisor to Senator Joseph McCarthy, and it is possible that McCarthy first learned of Lattimore through Kohlberg.
Lattimore was a combative witness and waged verbal duels with McCarthy. In April 1950, the surprise witness, Louis F. Budenz, former editor of the Communist Party organ Daily Worker. testified Lattimore was a secret Communist, but not a Soviet agent, that is, he was a person of influence who often assisted Soviet foreign policy. Budenz said his Party superiors told him Lattimore's “great value lay in the fact that he could bring the emphasis in support of Soviet policy in non-Soviet language.” The majority report for the Tydings committee cleared Lattimore of all charges against him; the minority report accepted Budenz's charges.
In February 1952, Lattimore was called to testify before the Senate Internal Security Subcommittee (SISS), headed by McCarthy's ally, Senator Pat McCarran. Before Lattimore was called as witness, investigators for the SISS had seized all of the records of the Institute of Pacific Relations (IPR). The twelve days of testimony were marked by shouting matches which pitted McCarran and McCarthy on one hand against Lattimore on the other. Lattimore took three days to deliver his opening statement; the delays were caused by frequent interruptions as McCarran challenged Lattimore point by point. McCarran the used the records from the I.P.R. to ask questions that often taxed Lattimore's memory. Budenz again testified, but this time claimed that Lattimore was both a Communist and a Soviet agent. The Subcommittee also summoned scholars. Nicholas Poppe, a Russian émigré and a scholar of Mongolia and Tibet, resisted the committee's invitation to label Lattimore a communist, but found some of his writings superficial and uncritical. The most damaging testimony came from Karl August Wittfogel, supported by his colleague from the University of Washington, George Taylor. Wittfogel, a former Communist, said that at the time Lattimore edited the journal Pacific Affairs, Lattimore knew of his Communist background; even though they had not exchanged words on the matter, Lattimore had given Wittfogel a 'knowing smile'. Lattimore acknowledged that Wittfogel's thought had been tremendously influential, but said that if there had been a smile, it was a 'non-Communist smile'. Wittfogel and Taylor charged that Lattimore had done 'great harm to the free world' in disregarding the need to defeat world communism as a first priority. They also asserted that the influence of Marxism on Lattimore was shown by his use of the word 'feudal'. Lattimore replied that he did not think that Marxists had a 'patent' on that word.
In 1952, after 17 months of study and hearing, involving 66 witnesses and thousands of documents, the McCarran Committee issued its 226-page, unanimous final report. This report stated that 'Owen Lattimore was, from some time beginning in the 1930s, a conscious articulate instrument of the Soviet conspiracy', and that on 'at least five separate matters', Lattimore had not told the whole truth. One example: 'The evidence... shows conclusively that Lattimore knew Frederick V. Field to be a Communist; that he collaborated with Field after he possessed this knowledge; and that he did not tell the truth before the subcommittee about this association with Field....'
In 1952, Lattimore was indicted for perjury on seven counts. Six of the counts related to various discrepancies between Lattimore's testimony and the IPR records; the seventh accused Lattimore of seeking to deliberately deceive the SISS Lattimore's defenders, such as his lawyer Abe Fortas, claimed that the discrepancies were caused by McCarran deliberately asking questions about arcane and obscure matters that took place in the 1930s in the expectation that that Lattimore would not be able to recall them properly, thereby giving grounds for a perjury indictment. Within three years, the charges against him were dismissed.' The government dropped the charges after federal judge Luther Youngdahl set aside the perjury indictment on First Amendment grounds. In his book Ordeal by Slander, Lattimore gives his own account of this episode.
From 1963 to 1970, Lattimore was the first professor of Chinese studies at the University of Leeds in England, where he taught Chinese History, strongly illustrated with personal reminiscences. He died in 1989.
In An Inner Asian Approach to the Historical Geography of China (1947), Lattimore explored the system through which humanity affects the environment and is changed by it, and concluded that civilization is molded by its own impact on the environment. He lists the following pattern: