He was defeated in his re-election bid in 1948, after which he accepted an appointment by President Harry S. Truman as a delegate to the United Nations General Assembly and served as a special assistant to Secretary of State Dean Acheson during the formation of the North Atlantic Treaty Organization (NATO).

[6][7] At the time of John Sherman Cooper's birth, his father was serving as collector of internal revenue in Kentucky's 8th congressional district, a position to which he had been appointed by President Theodore Roosevelt.

[12][18] Cooper supported the governor's plan to provide free textbooks for the state's school children and sponsored legislation to prohibit judges from issuing injunctions to end labor strikes, although the latter bill did not pass.

[23] Following the cessation of hostilities, Cooper served as a legal advisor for the 300,000 displaced persons in his unit's occupation zone seeking repatriation after being brought to Germany as slaves by the Nazis.

[21] With these two factors working against Brown, Cooper won the election to fill Chandler's unexpired term by a vote of 327,652 (53%) to 285,829 (46%), the largest victory margin by any Republican for any office in Kentucky up to that time.

[9] Cooper was made chairman of the Senate Subcommittee on Public Roads, and helped draft a bill authorizing $900 million in federal funds to states for highway construction.

[9] He worked with fellow Kentuckian Alben Barkley and Oregon Senator Wayne Morse to undermine Jim Crow laws enacted by the states and remove obstacles to suffrage for minorities.

[33] The Democratic-leaning Louisville Times endorsed Cooper, but the presence of Kentucky's favorite son, Alben Barkley, on the ballot as Harry S. Truman's running mate in the 1948 presidential election ensured a strong Democratic turnout in the state.

[33][34] Both Barkley and Clements stressed party unity during the campaign, and although Cooper polled much better than the Republican presidential ticket, he ultimately lost to Chapman in the general election by vote of 408,256 (51%) to 383,776 (48%) .

[36] Political historian Glenn Finch observed that, while Cooper was well-qualified for his duties at the U.N. and NATO, his presence abroad also made him less available to campaign for the Senate seat vacated by Barkley's elevation to the vice-presidency.

They now feared that the election of a Republican would allow that party to organize the Senate, giving key committee chairmanships to isolationists opposed to continued US involvement in the Korean War.

[47] U.S.–India relations were strained, however, because of India's recognition of Communist China, its opposition to the Southeast Asia Treaty Organization (SEATO), and its resistance to foreign interference in Indochina.

[9][52] Twice divorced, Shevlin was the daughter of Robert A. Rowan (a wealthy California real estate developer whose projects included the Hotel Alexandria and the Security Building), step-daughter of Vatican official Prince Domenico Orsini, and a well-known socialite.

[58] Cooper labored to help officials in Washington, D.C. understand that India's reluctance to align with either the West or the Communists in China and the Soviet Union was their way of exercising their newly won independence.

[64] Prime Minister Nehru announced his intent to file a formal protest with the United States over the communique and to address the Indian Parliament about the matter.

[68] In August 1956, Congress approved a financial aid package for India that included the largest sale up to that point of surplus agricultural products by the United States to any country.

[9] Because Barkley's death occurred after the filing deadline for the November elections, the Democratic State Central Committee had to choose a nominee for the now-open seat.

[70] After unsuccessfully attempting to find a compromise candidate that both the Clements and Chandler factions could support, they chose Lawrence Wetherby, whose term as governor had recently expired.

[75] Shortly after his election as president in 1960, Kennedy chose Cooper to conduct a then-secret mission to Moscow and New Delhi to assess the attitudes of the Soviet government for the new administration.

[12] Cooper attended 50 of the 94 hearings and rejected the single-bullet theory stating that "there was no evidence to show that [Kennedy and Texas Governor John Connally] were hit by the same bullet.

[13] An advocate for small businesses and agricultural interests, Cooper opposed an April 1965 bill that expanded the powers of the Federal Trade Commission to regulate cigarette advertising.

[96] In January 1966, Cooper accompanied Secretary of State Rusk and Ambassador W. Averell Harriman on an official visit to Philippine President Ferdinand Marcos as part of a widely publicized "peace drive".

[9][27] In the lead-up to the 1968 Republican presidential primary, he endorsed New York Governor Nelson A. Rockefeller, saying that Americans would only support a candidate who took a clear position on Vietnam.

[73] In the Senate, Cooper helped lead the opposition to the development and deployment of anti-ballistic missiles (ABMs), putting him at odds with many in his party, including President Nixon.

[9] The measure failed by three votes but increased congressional scrutiny of the Defense Department budget, leading to a reduction in funding and hastening Strategic Arms Limitation Talks with the Soviets.

[108] In 1971, Church, Mansfield, and George Aiken convinced Cooper to help them write an amendment to end U.S. involvement in Southeast Asia altogether, but ultimately, the measure did not have the support to pass and was abandoned.

[108] Seventy-one years of age and becoming increasingly deaf, Cooper announced to the Kentucky Press Association on January 21, 1972, that he would not seek re-election to his Senate seat,[109] having served longer in that body than any other Kentuckian except Alben Barkley.

[27] The lame duck Cooper decided to make one more attempt to end the war, after an aggressive North Vietnamese offensive against the South in March 1972 intensified fighting in the region once again.

[116] Opponents of the measure in both Kentucky and Tennessee (the recreation area spans the two states) cited a variety of reasons to retain the old name, and the proposal was eventually dropped at Cooper's request.

[1] Because of his extensive support of rural electrification as a senator, the East Kentucky RECC was renamed the John Sherman Cooper Power Station in his honor.