The process of choosing national and local officials in the United States begins with registering potential voters to participate in elections.
Every American citizen 18 and older, with few exceptions, is eligible to take part in elections.
In the 2008 U.S. presidential contest, 63.6 percent of those eligible to vote did so.
The U.S. differs from many countries in that the national government does not regulate elections. While the right to vote is guaranteed by the U.S. Constitution, and the minimum age of 18 is set by federal law, the 50 U.S. states set the registration rules.
In some states, one can register to vote on election day. In other states, registration closes before the election. States also have various rules regarding residency, which affects whether someone can register there.
The two major U.S. parties -- the Democrats and the Republicans -- work to expand their size and influence through voter registration.
"It's crucial for us to get out to everybody and get them registered, and lined up ready to vote," says Ina Taylor, a Democratic Party official in the mid-Atlantic state of Maryland explaining that finding new people is as important as mobilizing the party regulars on Election Day.
Maryland Republican Party official Fred Fleischman calls registration an essential part of gaining and holding political power.
"In the state of Maryland, [with Republicans] being a minority party, it's very critical for us to register as many voters as possible so we have enough muscle, so we can compete on an even playing field with the other party," he says.
In some states, voters register as members of a given political party, while in others they do not. But people in every state can also register as independents. In some states, party affiliation is required to take part in preliminary elections called "primaries" that determine each party's candidate in the general election. But in other states, independents can take part as well.
Voter registration is also promoted by groups such as racial and ethnic minorities. This is to help ensure that elected officials know their concerns and respond to them.
"It's so important, especially with me being an African American," says Zebediah Daniels, a newly registered voter. "I feel our people fought for this, and it's very important that our people get out and continue to vote because it's such a rich privilege."
A federal law passed in 1995 allows people to register to vote while getting a driver's license, and a handful of states now permit voters to register via the Internet. Proponents say it is yet another way to increase participation in the election process that makes the U.S. a democratic nation.