For much of the 19th century and into the 20th century, there was a quaint custom called “Notification Day” which came several weeks after the convention, and involved the national committee men coming to the home of the candidate and officially “notifying” him the party’s nomination, which he then accepted in a speech.
In 1920, U.S. Senator Warren Harding was in Chicago during the Republican Convention which nominated him but remained at his campaign hotel headquarters and made no acceptance speech and did not appear before delegates; his wife Florence Harding was also overtly political like Nellie Taft and had helped to manage her husband’s campaign during the primaries.
She sat in a prominent place overlooking the convention floor, interacting with delegate and being sought out by reporters, with whom she openly discussed the machinations and proceedings behind each day of balloting at the 1920 Republican National Convention proceedings.
Thus, she became the first candidates’ spouse to witness her husband being nominated.
That year’s Democratic candidate’s spouse, Margaretta Cox did not attend the convention which nominated her husband, James Cox.
Herbert Hoover broke the custom by appearing at the 1928 Republican National Convention but his wife Lou sat in the balcony watching and listening to his acceptance speech. Democratic candidate Al Smith’s wife Catherine Smith did likewise at the convention nominating her husband.
Although Franklin D. Roosevelt attended the 1932 and 1936 conventions which nominated him for a first and second term, he did not appear at the convention which nominated him in 1940. Having also attended him at the first two, his wife Eleanor Roosevelt went alone to the 1940 one, making a speech to delegates, the first candidate’s spouse or First Lady to do so.
Theo Landon “refused” to join her husband Alf at the 1936 Convention in Chicago which nominated him as the Republican presidential candidate, explaining to the press that protecting and raising her two young children (one of whom grew up to become Nancy Kassenbaum, U.S. Senator from Kansas) meant she was “needed at home.”
In 1944, Thomas Dewey attended the Republican Convention which nominated him as the presidential candidate in Chicago and was joined by his wife Frances there. FDR did not go to the Chicago Democratic National Convention which nominated him for his fourth term. It occurred during World War II and was he was then holding meetings in the South Pacific. Eleanor Roosevelt did not attend either. This was the last time that a nominated presidential candidate did not attend the convention. However, the Democratic vice presidential candidate’s spouse, Bess Truman, did attend. In less than a year, due to President Roosevelt’s death in April of 1945, she would be First Lady.
In 1948, both incumbent President and Democratic candidate Harry Truman and his opponent, Republican presidential nominee Dewey attended the conventions which nominated them and made acceptance speeches. Both conventions were held in Philadelphia.
Both Bess Truman and Frances Dewey watched the proceedings. Mrs. Dewey did go to the podium, where she watched from behind her husband with others to hear him deliver his acccptance speech.
In 1952, the Democratic candidate Adlai Stevenson was divorced. That year, the Republican presidential nominee Dwight Eisenhower was joined by his wife Mamie Eisenhower at the podium and she was welcomed and acknowledged there by the delegates – but she did not speak.
In 1956, Stevenson and Eisenhower again ran against each other and Mamie Eisenhower again appeared at the podium but did not speak.
In 1960, Republican presidential nominee Richard Nixon was joined at the podium by his wife Pat Nixon.
However, since she was pregnant, Jacqueline Kennedy did not attend the Democratic National Convention which nominated her husband in Los Angeles.
This was the last time a candidates’ spouse of either party did not appear at the convention which nominated her husband.
Ever since then, the wife of the nominee of each party has been a highly visible figure during the convention week. The list includes:
1964, Lady Bird Johnson (D) and Peggy Goldwater (R)
1968, Pat Nixon (R) and Muriel Humphrey (D)
1972, Pat Nixon (R) and Eleanor McGovern (D)
1976, Rosalynn Carter (D) and Betty Ford (R)
1980, Nancy Reagan (R) and Rosalynn Carter (D)
1984, Nancy Reagan (R) and Joan Mondale (D)
1988, Barbara Bush (R) and Kitty Dukakis (D)
1992, Hillary Clinton (D) and Barbara Bush (R)
1996, Hillary Clinton (R) and Elizabeth Dole (R)
2000, Laura Bush (R) and Tipper Gore (D)
2004, Laura Bush (R) and Teresa Kerry (D)
2008, Michelle Obama (D) and Cindy McCain (R)
2012, Michelle Obama (D) and Ann Romney (R)