Voting power in the Electoral College: The noncompetitive states count, too

In U.S. presidential elections, voters in noncompetitive states seem not to count—and so have zero voting power, according to the Banzhaf and other voting-power indices—because they cannot influence the outcome in their states. But because the electoral votes of these states are essential to a candidate's victory, it seems that they do count, but in a different way. We measure the power of voters in noncompetitive states by modeling how these states structure the contest in the competitive states, as illustrated in the 2012 election. Barack Obama’s lead of 46 electoral votes over Mitt Romney in the 41 noncompetitive states and the District of Columbia gave him 5.5 times as many ways of winning in the 9 competitive states as Romney had. Also, Romney’s winning coalitions were weaker by two additional measures: They were 2.4 times more vulnerable, and 5.5 times more fragile than Obama’s. Compared with being tied with Romney in the noncompetitive states, Obama’s lead in these states contributed very substantially to his victory.