U.S. Democratic presidential candidate Senator Barack Obama (D-IL) has his cheek touched by 7-month-old Aedyn Buchanan as he visits diners at Stephanie's II homestyle restaurant in Greensboro, North Carolina, May 5, 2008.(Xinhua/Reuters Photo) Photo Gallery>>>

Democratic presidential candidate Senator Hillary Clinton (D-NY) speaks during a campaign stop at the Merrillville Fire Department Station #2 in Merrillville, Indiana, May 5, 2008.(Xinhua/Reuters Photo) Photo Gallery>>>

    By Yang Qingchuan

    WASHINGTON, May 6 (Xinhua) -- Sen. Barrack Obama of Illinois and rival Sen. Hillary Clinton of New York are competing fiercely in the North Carolina and Indiana primaries Tuesday, the latest critical day in the Democratic presidential nomination race.

    For front-runner Obama, the primaries present an opportunity to wipe out doubts about him being a "flawed" candidate in the general election.

    It could also be an opportunity for Clinton to make the case that Democratic voter sentiment is swinging in her favor, and thereby cut into Obama's lead in pledged delegates and in the popular vote.

    The results of Tuesday's primaries will be important for both candidates.

    After all, the largest number of national convention delegates are at stake now than during the remaining primary season.

    There are 72 convention delegates at stake in Indiana and 115 in North Carolina.

    However, barring the most unexpected-- a blowout in either state, or twin victories by either Obama or Clinton -- the more likely outcome is a continued and inconclusive fight.

    THREE SCENARIOS

    There are basically three likely scenarios at the end of Tuesday's primaries.

    First, Clinton wins Indiana and North Carolina. But analysts say this scenario will be most unlikely, based on pre-election polls.

    Obama seems to hold a formidable advantage in North Carolina where African Americans account for a large chunk of Democratic voters while Clinton's best chance is to win Indiana with the support of white blue-collar workers.

    Scenario number two: Obama wins North Carolina and Indiana, which would almost certainly mean lights out for the Clinton campaign.

    Clinton can keep fighting but the pressure will probably be insurmountable.

    Several of her advisers have said they would counsel her to quit the race if she lost both.

    However, recent surveys show Clinton is gaining momentum in Indiana and she led Obama in pre-election polls.

    The third likely outcome is that candidates split the votes, with Clinton winning Indiana and Obama winning North Carolina, which would almost surely mean the struggle will continue.

    This is the most likely outcome, given the demographic patterns in the Democratic race.

    Obama has consistently claimed the allegiance of young voters, African Americans and voters who are better educated and wealthier.

    Clinton has equally strong backing from women, less-educated voters and the economically hard-pressed.

    In states where Obama's demographic groups hold sway, he wins. Where Clinton's do, she is victorious.

    If the pattern holds, that makes Obama the favorite to win North Carolina and gives Clinton the edge in Indiana.

    That scenario would give each candidate incentive to keep running at least until June 3, the last day of the primary season.

    "As long as he wins where he's supposed to win, and she wins where she's supposed to win, the nature of the race is fundamentally unchanged," said Ben Tulchin, a Democratic pollster watching the race from the sidelines. "And so it continues."

    NO SINGLE DECISIVE PRIMARY

    After Indiana and North Carolina, there will be only six primaries left for the Democratic nomination battle.

    All are important, but none will be decisive.

    The six contests line up in predictable fashion: Clinton should easily win West Virginia on May 13, Kentucky on May 20 and Puerto Rico on June 1.

    Obama is heavily favored in Oregon on May 20, and Montana and South Dakota on June 3.

    As a result, the final contests will have little effect on the delegate count.

    The real answer, as the Washington Post's Dan Balz suggested, lies in Michigan and Florida,

    The two states, both of which favor Clinton, were deprived of their representation at the Democratic National Convention in August because they moved up their primary date without approval from the Democratic National Committee.

    But the issue remains unresolved, and Clinton continues to press for a solution that would give her a boost in the delegate count.

    The most important date on the calendar could be May 31, when the Democratic National Committee's Rules and Bylaws Committee meets to consider the matter.

　　IT'S UP TO THE SUPERDELEGATES

    With just a handful of smaller states left to vote after Tuesday, Obama and Clinton are not looking to surprise voters or build traditional political momentum.

    Rather, they are aiming to impress a small but important audience: the more than 250 Democratic Party officials, or superdelegates, who have yet to publicly back a candidate.

    That means Clinton, who trails in the overall delegate count, is the one praying for lightning to strike.

    "The onus is on her. She's got to do better than tie," Clinton backer James Carville told Newsweek recently.

    Obama's aides said they expect Indiana to be close, downplaying Obama's own earlier suggestion that the state would be the race's "tiebreaker".

    Clinton aides, meanwhile, argue that Obama needs to beat her soundly in North Carolina.

    Most polls suggest relatively narrow margins.

    Obama led by seven percentage points in North Carolina in Monday's polls while Clinton led in Indiana by five percentage points.

    Results on that scale would give neither candidate a dramatic boost in the delegate chase.

    Unless there is a runaway winner in the final stages of the Democratic primary season, superdelegates could face an unpalatable choice: hand the nomination to a candidate who limps to the finish a month from now, or overturn the will of voters and face a backlash among African Americans and young people energized by Obama's promised break from the past.

    The greatest beneficiary, many Democrats fear, will be Sen. John McCain of Arizona who in effect wrapped up the Republican nomination in February and now runs even with either of the two Democrats in national polls.

Special Report: U.S. presidential election 2008