No US President in Astrodatabank has ever had a Sun-Chiron conjunction within 3 1/4 degrees. Some famous politicians who have had this aspect in Astrodatabank:

Cruz Bustamente (Lt. Governor of CA; lost to Ahnold in CA Recall '03)

Bruce Babbitt (AZ Governor who ran for President and did not win the nomination; he went on to serve as secretary of Interior under Clinton and revitalized the National Park Service and helped endangered species)

Bob Kerry (American politician and entrepreneur, the senior Senator from Nebraska, Vice Chairman of Senate Select Committee and a member of Senate Finance Committee and Senate Agriculture Committee. Viewed by some as a formidable challenger to Al Gore in the Presidential race, Kerrey declined to pursue a Presidential bid. He further announced that would not seek re-election in 2000 as he wants to tend to his spiritual side, "a deeply personal decision.")

Huey P. Long (American lawyer and politician, former Governor of Louisiana and U.S. Senator, known for his absolute power during his governor years that earned him the title of "Dictator of Louisiana." Lecherous and corrupt, he was nonetheless a beloved and popular man. was shot by an assassin while walking down a State Capitol corridor. Taken to the hospital, he was treated for a puncture of the colon, but a more serious kidney wound was overlooked, and he died soon after.)

Ralph Dills (American politician, California senator who introduced a bill to the Senate to license professional astrologers in 1975, a bill sponsored by PAI (Professional Astrologers Inc).)

Eugene Shoemaker (American astrogeologist and U.S. government official. He has the distinction of being the first person to have a lunar burial as his ashes were aboard NASA's Lunar Prospector which crashed into the earth's Moon. He had always wanted to make a space shot with the astronauts but died in a car accident in 1997.)

Richard M. Daley (elected to Chicago mayor in '88; prior prosecuting attorney. Named a significant number of minorities to key positions. His father Richard J. Daley was a legendary Chicago governor; Richard M. became very successful and was able to come out into his own from underneath his father's impressive shadow). Richard M. has Sun-conjunct Chiron in Taurus, which I find some evidence for being Chiron's exaltation. Shirley Temple, Audrey Hepburn, and Andruw Jones also have the conjunction in Taurus.

Oveta Culp Hobby (When WW II began, she joined the WAACs from 1942-1945; she was promoted to Major, then Colonel. On 2/21/1953 she was appointed the Secretary of the Department of Health, Education and Welfare of President Eisenhower's cabinet.)

Dorothy Day (American activist in the Catholic Worker's Union. As a pragmatic idealist, she made a major impact on American Catholicism as she struggled for unions, higher wages and better conditions.
Before joining the church in 1927 she was a young bohemian pacifist, a political radical, feminist and reporter. Later in her life she was called a saint for seeking to see Christ in everyone.) Dorothy Day, like Howard Dean, has the conjunction in Scorpio.

Neville Chamberlain (British Prime Minister 1937-1940; famous for his policy of "appeasement;" thought he had worked out a peace treaty with Hitler)

Harold Wilson (became Prime Minister of UK 3/04/74 upon Edward Heath's resignation; a spokesman for the left wing of the Labour Party)

Angela and Maria Eagle (British politicians. They both ran for Parliament at the same time; Angela won the seat of Member of Parliament and Maria lost the election.)

Tommy Sheridan (Scottish politician, a district councilor jailed for anti-poll-tax activities. Running his campaign from prison, he was freed and elected.)

Eduard Benes (Czechoslovakian P.M. '21-'22 and President '35-'38 and '45-'48; From 1941-1945 he served as the head of the provisional Czech government while in exile)

Juan Peron (Argentinian President 1946-1955; wife Eva Peron [famous in movies by Madonna's role in "Eva"]. Though criticized for his fascist sympathies, he was wildly popular for his nationalistic and reformist appeals to the urban working class). Perons had Sun-Mars-Chiron tightly conjunct.

Ernesto Zedillo (Mexican politician, a bland and enigmatic man elected the new Mexican president 8/21/1994. He was an accidental candidate, hurriedly chosen after Colosio was gunned down 3/23/1994. When Zedillo devalued the peso on 12/20/1994, it plummeted, starting a stunning disintegration of Mexico's economy.)

Rudolf Diels (German first chief of the Gestapo. He had a reputation as a heavy drinker and made rash statements publicly; however, he had an unquestioning loyalty and subservience to Hitler. He died Nov. 18, 1957, accidentally shooting himself while on a hunting trip.)

Prince Simeon II (Bulgarian royalty, the Crown Prince. He was the pretender to the throne from age six when his dad, Boris III, was assassinated 8/28/1943.)

The following is not exactly political: Charles M. Schwabb (American steel king, an entrepreneur in shipbuilding who branched into munitions and armaments. He was the first president of U.S. Steel in 1901 and assumed control of Bethlehem Steel Corp, directing its growth into shipbuilding, munitions and allied fields. He started as a stake driver at one dollar a day and studied engineering at night.)

As I studied a number of Sun-Chiron people (other than politicians), it is amazing how many "cinderella" stories there are (this term came about through the Magi Society, I believe):

Queen Elizabeth II, Shirley Temple, Audrey Hepburn, Cary Grant, Doris Day, Kevin Kostner, Deepak Chopra, Mae West, Christian Dior, George Westinghouse, Charles M. Schwabb (American steel King, early 1900's), Waylon Jennings, Malcolm Young (AC/DC), Billy Corgan (Smashing Pumpkins) Joe Torre (current NY Yankee skipper), Andruw Jones (HR in his first two World Series at-bats at Yankee stadium).

There are at least a couple great "Cinderella" success stories for the Sun-Chiron conjunct politicians above, but you can see that most of the political stories are not mega-powerful in nature, or at least have some serious flaw. In film, music, fasion, and sports, however, there are many nice Cinderella stories, without so many weak or tragic stories as there are in the political realm.

The 'best' placement for these Sun-Chiron conjunctions MAY be the Venus-ruled signs and Capricorn:
Taurus: Shirley Temple, Audrey Hepburn, Richard M. Daley, Andruw Jones
Libra: Juan Peron, Deepak Chopra, George Westinghouse
Capricorn: Cary Grant, Waylon Jennings, Kevin Costner, Oveta Culp Hobby