This coming Tuesday, February 5, will be the most important day yet in the U.S. presidential race.  More than 20 states are holding primaries, caucuses or state conventions to select party delegates to the national nominating conventions later this year.  VOA national correspondent Jim Malone has a preview.

The remaining two Democratic contenders, Hillary Clinton and Barack Obama will compete in 22 contests on February 5 with more than 1,600 delegates at stake.

A total of 2025 delegates are needed to secure the Democratic Party's presidential nomination at the national convention in late August in Colorado.

With former senator John Edwards now out of the Democratic race, Obama presents himself as the clear alternative for change.

"It is time for a new generation of leadership," he said.

Clinton counters with an emphasis on experience.

"The decision facing Georgia on Tuesday and all of the Super Tuesday states is who will be the best president on day one, to meet those challenges and seize the opportunities," she said.

Clinton is focusing her efforts on winning delegates in larger states like California, New York and New Jersey, where the polls give her an edge.

Obama hopes to do well in his home state of Illinois and in Massachusetts, where he has the support of Senators Ted Kennedy and John Kerry.  The Obama campaign is also targeting smaller states in the South, Midwest and the Plains.

Democrats use a proportional system of allocating delegates, which means even though one candidate may lose a state primary or caucus, that candidate will still win some portion of the nominating delegates.

Experts say that means the Democratic race is likely to extend beyond February 5.

"I do think that you are not going to come out of February 5 with somebody with an enormous lead in delegates," said John Fortier, who monitors U.S. politics at the American Enterprise Institute in Washington.  "Even a pretty solid win by one of the candidates would probably be 55 percent of the delegates to 45 percent.  That still leaves open the possibility that later states could change the outcome."

The remaining Republican contenders will also face what amounts to a national primary on February 5.

More than 1,000 Republican delegates are at stake in 21 state contests next Tuesday.  A total of 1,191 delegates are needed to win the Republican nomination at the national convention in Minnesota in early September.

Senator John McCain of Arizona is now the frontrunner in the Republican race following his victory in the Florida primary.

"I am prepared to lead our party and the nation and I am prepared and am succeeding in uniting it.  We need all parts of our party together if we are going to win in November," he said.

McCain's surge in the Republican race is winning him some high profile endorsements.  Former New York City mayor Rudy Giuliani withdrew from the presidential race on Wednesday after a poor showing in Florida and threw his support to McCain.

On Thursday, McCain also won the endorsement of California Governor Arnold Schwarzenegger.

"He is a fantastic, outstanding public servant," he said.  "He is a great American hero and an extraordinary leader."

McCain's main remaining challenger is former Massachusetts governor Mitt Romney.  Former Arkansas governor Mike Huckabee and Texas Congressman Ron Paul are also in the race, but trail in the polls.

Romney argues that he is the candidate of change among the Republican contenders.

"Washington is fundamentally broken," he said.  "We are not going to change Washington by sending the same people back just to sit in different chairs."

The latest polls give McCain an advantage in some of the larger states voting on Super Tuesday including California, New York and New Jersey.

Analyst John Fortier says the recent endorsements by Schwarzenegger and Giuliani should help McCain.

"He is likely to take all of those Giuliani votes, or a significant number of them, and [that should] help him especially in the Northeast where he has a pretty clear lead in many of the Northeastern states that hold contests on February 5," he added.

The Republican nomination fight could be settled sooner than the Democratic battle, because most of the Republican primaries and caucuses are winner take all events, which only award delegates to those who finish first in a given contest.