While millions of Americans will cast ballots for president on November 4, their votes do not directly send one of the candidates to the White House. In this segment of How America Elects, VOA's Jeffrey Young explains that the selection of the president is actually done by the Electoral College.

On December 15, a total of 538 people will assemble in the 50 states and the District of Columbia, and cast ballots. These people are Electors in an institution called the Electoral College. It was set up under the U.S. Constitution to elect the president.

Professor Curtis Gans at American University describes how each state's number of Electors is determined. 

"Those Electors are, in number, [equivalent to] the Congressional delegation in each state - - two for the Senate, and however many Representatives. And, they are elected by a winner-take-all in the states," Gans explained.

Two states, Nebraska and Maine, are an exception to the winner-take-all rule. They assign Electors proportionately according to the popular vote.

George Washington University Professor Dennis Johnson says the Democratic and Republican Parties are fixated on capturing a majority of the 538.  

"When you think about the strategy of an election, the most important number is 270. And that is the number of Electors that will get you over the top [get you elected president]. And, any combination of states that has 270, that is the magic number that you are really looking for," Johnson said.

But each candidate's pursuit of these states is different, as Professor Gans explains.

"Every candidate in this polarized country, at this point, starts with a number of states that are clearly their states to win, and a number of states that are their states to lose," Gans said.

In the middle, there are states that could go to either candidate. That's where Democrats and Republicans mount their biggest efforts.

"You have to make really hard choices when you go out there [campaigning] - on where you are going to campaign, where you are going to put your dollars, [and] where you are going to put your effort to get that 50 percent plus one [vote in each state] that takes you over the top," Peter Fenn, a Democratic marketing strategist said.

The states that could go for one candidate or the other are called "battleground" states. Sometimes, the battles have become national dramas.

It happened in 2000, in the contest between Democrat Al Gore and Republican George W. Bush.  Gore had won the national popular vote by a half-million votes.

But, in Florida, the vote was so close a recount was started. Both sides fought for weeks over the way the recount was conducted.

The Bush team took the issue all the way to the U.S. Supreme Court.  On December 13, it effectively ended the recount. Florida's 25 electoral votes put George W. Bush in the White House with 271 Electors to Al Gore's 266.

Both parties are so entrenched in the current Electoral College that Professor Dennis Johnson doesn't expect a change to a proportional system or direct voting.

"The parties are kind of looking over the strategy, and looking over the map, and saying 'You know, for us, no, let's keep it the way it is - winner take all," Johnson said.