This year's group of swing states is therefore smaller. The list includes Arizona, Georgia, Michigan, Pennsylvania and Wisconsin, according to David Schultz, a political science professor at Hamline University and law professor at University of Minnesota.

The National Popular Vote Interstate Compact (NPVIC) is an agreement among a group of U.S. states and the District of Columbia to award all their electoral votes to whichever presidential ticket wins the overall popular vote in the 50 states and the District of Columbia.

How does California select its electors? On or before October 1 of the presidential election year, each party's nominee must file a list containing the names, addresses, and telephone numbers of the 54 electors pledges to him/her. Each party determines its own method for selecting electors.

New electors are chosen for each election, and at the conclusion of their duties, they disband. The Electoral College has evolved since its establishment in 1787. Constitutional amendments have improved the Electoral College, and over time States have altered the ways they have im- plemented it.