Tipping-point state

The concept of a "tipping-point state" is used in some analyses of United States presidential elections. In a list of states ordered by decreasing margin of victory for the winning candidate, the tipping point state is the first state where the combined electoral votes of all states up to that point in the list give the winning candidate a majority in the Electoral College.

The idea of a "tipping-point state" can be interpreted as suggesting a counterfactual, on the assumption that outcomes in different states are strongly correlated: if the nation-wide vote margin were shifted, but the order of states by vote margin were unchanged, the tipping-point state would be the state or states in which a change in the state winner would result in a change in the national winner. The term may also refer to the state that would give the second-place candidate a majority of the electoral vote when all states are arranged in order of their vote margins; this is typically, but not always, the same state as in the primary definition (see section Origin and definition for exceptions).

Since the number of electors was set to 538 for the 1964 United States presidential election, 270 electoral votes have been required to win the Electoral College.

In some elections, there can be multiple tipping-point states for different candidates: if no candidate receives 270 electoral votes, a contingent election is required in the United States House of Representatives. For example, in the 2020 United States presidential election, if Donald Trump had won Wisconsin, Arizona and Georgia, the electoral college would have been tied 269-269: thus, Wisconsin was the tipping-point state for a Biden victory, whereas Pennsylvania, the next-closest, was the tipping-point state for a Trump victory.