The 1912 United States presidential election in South Dakota took place on November 5, 1912, as part of the 1912 United States presidential election. Voters chose five representatives, or electors, to the Electoral College, who voted for president and vice president.
South Dakota voted for the Republican nominee, former president Theodore Roosevelt, over the Democratic nominee, New Jersey Governor Woodrow Wilson, by a margin of 8.49%.
Despite incumbent president William Howard Taft winning the national Republican nomination, the South Dakota Republican Party, under the control of progressives and heavily influenced by senator Coe I. Crawford, instead nominated electors pledged to Theodore Roosevelt, with the Progressive Party not appearing on the ballot. This selection proved controversial with conservative Taft supporting Republicans who unsuccessfully attempted to overturn the decision in court. As a result, South Dakota was the only state in the 1912 election not to have president Taft either on the ballot or as a write in option (as in California). The state's other senator Robert J. Gamble, who supported Taft, predicted that the anger amongst conservative Republicans was such that many would support Woodrow Wilson purely to defeat Roosevelt. Despite this Roosevelt carried the state albeit with a much reduced margin from Taft's victory in 1908.
With 50.56% of the popular vote, South Dakota would prove to be Roosevelt's strongest state in terms of popular vote percentage in the 1912 election and the only one in which he achieved a majority of the vote. This was the only non-former Confederate state to give any candidate an absolute majority of the vote.
A primary for the Democratic presidential candidate was held in South Dakota on June 4, 1912. The race was between four competing slates of national delegates. The first slate to announce its candidacy was aligned with the faction of the local Democratic Party supporting Edwin S. Johnson's campaign for the Democratic nomination for governor. This group ran under the motto "Wilson-Bryan Progressive Democracy" and pledged to support Woodrow Wilson as its first choice for the presidential nomination, with William Jennings Bryan as a second choice should he become a viable candidate. If neither Wilson nor Bryan were available, the delegates were bound by their motto to support a progressive candidate.
In March, the South Dakota Democratic State Central Committee announced its support for the candidacy of P. F. Wickhem in opposition to Johnson and that they would name a ticket with the motto "Wilson-Clark-Bryan Democracy" to oppose Johnson faction candidates at all levels. On 10 April, the Wickem faction filed its list of delegates to the national convention under the title "Wilson-Clark-Bryan Democracy". These delegates were favourable to either Wilson or Champ Clark, with Bryan as a third choice if viable.
Former Senator Richard F. Pettigrew, who had recently assisted Clark's campaigns in Illinois, Iowa, Nebraska, and other states, returned to South Dakota to find the Democratic electorate divided between two tickets that both placed Wilson first in their mottos. Seeking to create a slate that would give Clark first preference, Pettigrew entered negotiations with the Wickhem faction, which he considered receptive after Wickhem's campaign was weakened by the publication of a telegram he had sent to Senator Alfred B. Kittredge opposing the Hepburn Act.
On 7 May, the Wilson-Clark-Bryan Democracy switched its support from Wilson to just Clark. Lee, head of the slate, stated that:
Later, a slate of electors under the motto "Clark for President" and one for a man named Homber B. Brown entered the race. The Wilson-Clark-Bryan Democracy accused the Clark for President slate of being an attempt to split the Clark vote and sought its removal from the ballot. The Secretary of State of South Dakota refused to withdraw the third ticket, but as both tickets were publicly known to support Clark, stated that the votes of both should be acredited to Clark.
As the combined vote of the pro-Clark slates exceeded that of the pro-Wilson slate, the Wilson-Clark-Bryan Democracy delegates were issued certificates under the law by the Democratic State Chairman. Later, the State Canvassing Board issued certificates to the Wilson-Bryan Progressive Democracy delegates.
The Democratic National Committee determined that the pro-Wilson delegates should be seated. This decision was overturned by the Convention's Credentials Committee, which voted 28-23 to seat the Clark delegates instead. F. H. Martin of Wisconsin, who voted against the reversal, took the matter to the floor of the convention. The convention voted 639.5-437 to adopt the minority report of the Credentials Committee, which seated the Wilson delegates.
A primary for the Republican presidential candidate was held in South Dakota on June 4, 1912. Theodore Roosevelt won all 10 delegates against Robert M. La Follette and William Howard Taft.