Final answer:
If the U.S. presidential election is decided by the House of Representatives, the winning candidate must receive at least 26 votes, with each state delegation in the House casting one vote.
Step-by-step explanation:
In the event that no presidential candidate receives a majority of Electoral College votes, the responsibility to elect the President of the United States falls to the U.S. House of Representatives. This is a rare occurrence with historical instances such as the elections of 1800 and 1824 providing precedent. When this happens, the House selects the President via a special voting process where each state delegation receives one vote, regardless of the number of representatives the state may have. A majority of states (currently 26 out of the 50) must agree on a candidate for him or her to win the Presidency. This voting by states is mandated by the 12th Amendment to the U.S. Constitution.
During such a contingency election, the candidate must receive the favorable votes from the majority of state delegations in the House. Each of the 50 states casts one vote, requiring the successful candidate to obtain at least 26 votes to secure the presidency. The vote is taken by ballot and a quorum for the vote requires members from two-thirds of the states. Moreover, the vote must be completed by a set deadline, otherwise the Vice-President shall act as President, as stipulated before the 20th Amendment altered this provision.