Understanding the USA Electoral College System

In each state, whichever party garners a majority of popular votes, regardless of how narrow the margin, wins all the electoral votes. By forcing residents in each state ultimately to vote as a block, the system is supposed to ensure that small states’ interests are not drowned out by those of larger states.

In all, there are 538 electoral votes and the number given to each state reflects the sum of the representatives and senators it sends to Congress. It takes 270 or more electoral college votes to win the election. The biggest states - California (54), New York (33), Texas (32), Pennsylvania (23) - have the most impact on the result of the presidential election.

Usually, the result is nearly the same as it would have been if the election were direct. Yet the system has produced presidents who received a minority of the popular vote but a majority of the electoral votes, including Harry S Truman, Woodrow Wilson, Abraham Lincoln and John Quincy Adams.

President Bill Clinton was also elected in 1992 with only 43 percent of the popular vote, but 370 electoral votes. Several times in recent electoral college history, a relatively small shift in voter preference in key states would have reversed election outcomes.