Nevada will be the first state with delegates (25 of them) at stake after the New Hampshire primary and could play an important role if the race is still competitive coming out of Northeast.

While party leaders estimate only about 40,000 voters will take part in Nevada's caucuses, all the major candidates have spent considerable resources here in hopes of securing a win among a Western, heavily Hispanic electorate.

The campaigns are all counting on momentum and strong organization to fuel their efforts here. The candidates are basing their organization on an Iowa caucus model, building relationships precinct by precinct.

Richardson has spent more time here than any other candidate, hoping to parlay his Hispanic heritage and proximity as governor of neighboring New Mexico into a strong showing.

All the campaigns are vigorously competing for the backing of the Culinary Union, which represents some 60,000 service workers along the Las Vegas strip. The union will announce an endorsement in early January.

South Carolina: Jan. 26

The three top-tier candidates have grounds to lay claim to South Carolina and its 45 pledged delegates — Obama and Clinton because of their popularity among black voters, Edwards because he was born in the state and won its primary four years ago.

Clinton and Obama have strong organizations in the state and have begun sustained television advertising recently. Both have made a concerted effort to woo black voters, who were 50 percent of primary voters in the state last time; they've run ads on black radio and sought endorsements from community leaders and black legislators.

Edwards has run television ads here since November and has made more campaign visits than Obama or Clinton. Polls show him running a distant third but slowly gaining ground.

Florida: Jan. 29

Like Michigan, Florida has been penalized for moving its primary in violation of party rules. The national party has stripped the state of its 185 delegates, and the candidates have pledged not to campaign in the state, although they have made several fund-raising visits.

Mega Tuesday: Feb. 5

Contests from Connecticut to California, including Utah, on this day could end up determining the Democratic nominee. At least 20 states will hold primaries and caucuses, assigning 2,075 delegates.

Clinton has seen her lead diminish somewhat in California, whose 441 delegates represent the day's largest prize. But the campaign is running generally strong there and is targeting absentee voters who can begin casting ballots Jan. 8.

The campaign is also building organizations in states holding caucuses on Feb. 5, including Minnesota, Colorado and Kansas.

Obama has bolstered efforts in California, and polls show him running strong in Georgia and Missouri. He's strongest in his home state of Illinois, while Clinton is dominant in her home state of New York and in nearby New Jersey.