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There are eight Democrats and eight Republicans running for President, but probably not for long. As voters cast ballots in primaries and caucuses—and with 21 states voting on February 5— nominees for both parties will probably emerge in the next couple of months. That's long before the parties will make it all official at next summer's conventions.

How Did The Primary System Come About?
In the 19th and early 20th centuries, politicians and officials chose presidential candidates at party conventions. Progressives began promoting primaries in the late 1800s, saying party bosses were cutting backroom deals to pick nominees. The first presidential primaries occurred in the early 1900s, but it wasn't until after World War II that they began to play a significant role in choosing candidates.

How Do Primaries Work?
With states voting separately, voters select their favorite candidate for their party's nomination. The state's delegates are allocated based on the results; they go to the convention, and formally pick the nominee. A Democratic candidate needs 2,104 out of 4,206 delegates to win the nomination; a Republican candidate needs 1,191 of 2,380 delegates.

What About Caucuses?
Some states, like Iowa, have caucuses rather than primaries. In caucuses, party voters generally gather at the district or precinct level to choose among delegates representing the various candidates.

What Happens at The Conventions?
In recent years, one candidate has collected enough delegates in early primaries to all but guarantee the nomination. But tight races are possible in both parties this time, which could lead to convention fights for either or both nominations.

Why Are Iowa and New Hampshire So Important?
In a word: tradition.
Since 1952, the New Hampshire primary has been the first big test of presidential hopefuls. The Iowa caucuses—held before the New Hampshire vote—began to gain clout in the 1970s. This year, other states have moved up their votes to increase their influence, but Iowa and New Hampshire have guarded their early-vote status.

Democratic National Convention
Aug. 25-28, Denver, Colorado

Republican National Convention
Sept. 1-4, Minneapolis-St. Paul, Minnesota

2008 DEMOCRATIC PARTY CANDIDATES

Joseph R. Biden Jr., Senator from Delaware
Hillary Rodham Clinton, Senator from New York
Christopher J. Dodd, Senator from Connecticut
John Edwards, Former Senator from North Carolina
Mike Gravel, Former Senator from Alaska
Dennis J. Kucinich, Congressman from Ohio
Barack Obama, Senator from Illinois
Bill Richardson, Governor of New Mexico

2008 REPUBLICAN PARTY CANDIDATES

Rudolph W. Giuliani, Former Mayor of New York City
Mike Huckabee, Former Governor of Arkansas
Duncan Hunter, Congressman from California
John McCain, Senator from Arizona
Ron Paul, Congressman from Texas
Mitt Romney, Former Governor of Massachusetts
Tom Tancredo, Congressman from Colorado
Fred Thompson, Former Senator from Tennessee and actor