Proportionate awarding of delegates and evenly-matched candidates could mean no clear Democratic winner will emerge after this week's Super Tuesday primaries, says a political analyst.

"We have had a narrowing of the field," John Fortier, research fellow at the American Enterprise Institute, told CTV's Question Period on Sunday.

New York Sen. Hillary Clinton and Illinois Sen. Barack Obama are the two main candidates left, with former North Carolina Sen. John Edwards dropping out this past week.

Obama and Clinton are in a close fight. The two have strength in different parts of the Democratic party, he said.

Combined with that, "the states on Feb. 5 are given proportionately, and so the delegates are going to be split relatively evenly. There may be a leader, but probably not a large leader after Feb. 5," Fortier said.

Clinton has the potential to become the first woman president of the United States, while Obama, if he is successful, would be the first African-American.

Obama's campaign received a major boost on Sunday with several high profile endorsements to add to that of the Kennedy clan.

At a rally at the University of California, Los Angeles, entertainment personalities Oprah Winfrey and Stevie Wonder as well as California's first lady Maria Shriver threw their support behind Obama.

Winfrey was introduced by Caroline Kennedy, who had endorsed Obama last month.

Winfrey referenced an incident in which a woman approached her recently to call her a traitor to her gender for not supporting Hillary Clinton.

"I'm a free woman," said Winfrey. "Being free means you get to think for yourself."

Appearances by Stevie Wonder and Maria Shriver were unscheduled and preceded a rousing speech by Obama's wife, Michelle, who told the crowd that "we can change the world."

"For the first time, we can just vote as we believe," Winfrey said. "This is what the struggle was for."

The issue of race has played a more significant role on the Democratic side than expected, Fortier said, referring to the days leading up to the South Carolina primary on Jan. 26.

"We saw then, coming out of the race, Obama doing very well and better than expected with the black community with a very large percentage of turnout, but also a very large percentage of the vote, so certainly those issues are out there," he said.

The strength of Clinton's campaign may depend partly on how it recovers from former President Bill Clinton's "attack dog" approach to Obama, which many say was ineffective and raised the black-white issue, he said.

"Since Obama won so decisively in South Carolina, a lot of people are thinking that was a bad tactic and are reminded of some of the dirtier tricks that people play and the Clintons have practiced over the years. So this week we've seen Clinton become quiet again. He's been a more controversial figure than we expected."

Added to that, the endorsement of the Kennedy family has added to Obama's perceived momentum.

"That's helpful to Obama. He's still not as well known as Hillary Clinton ... but he has the enthusiasm, he has young and independent voters and more educated voters, and add to that the African-American base and he's a very formidable candidate."

A key question is Obama's strength with the African-American vote outside the south, particularly in urban centres like New York, Chicago and Los Angeles, Fortier said.

Another key demographic are Hispanics. Clinton did well among them in Nevada, he said.

In California, "we're going to see a big Hispanic vote. Let's see how that vote breaks and that will tell us something about the strength of the two candidates going forward," Fortier said.

The Republicans

For the Republicans, Fortier feels a front-runner is beginning to emerge in the form of Arizona Senator John McCain.

"His wins in Florida and earlier have made him the favourite on Feb. 5. McCain has a national following, plays in all regions of the country, so it looks like he's the favourite to come out with a good lead in delegates and that would be hard to stop," Fortier said.

To validate McCain's frontrunner status, the south is a region to watch in the Republican race.

"One of the reasons that (former Massachusetts governor) Mitt Romney has trouble catching John McCain is that there is (former Arkansas governor) Mike Huckabee in the race, who can win among some Christian evangelicals," Fortier said.

That could especially help McCain in the South, where he is expected to do well, he said.

In the Northeast, some predict McCain will sweep areas that were potential strongholds for former New York City mayor Rudy Giuliani, who dropped out of the race to endorse McCain. Those places include New Jersey and Connecticut. They are "winner takes all" states, he said.

Faced with a troubled Republican administration and unpopular war in Iraq, Fortier thinks McCain is the best candidate the Republicans can put up against either Obama or Clinton.

"John McCain polls at least equal and sometimes ahead of Barack Obama and Hillary Clinton. He's probably the best candidate Republicans can put up there in a good Democratic year," he said.

Even though nearly 50 per cent of the delegates for both parties will be selected by Super Tuesday, a number of important contests will remain, with primaries in Virginia, Maryland and Washington DC holding theirs the following week.

"It will something more of a state by state (contest)," said Fortier. "We may see it drag out for quite a while."

In fact, the deciding factor may be un-pledged delegates, or so-called "super delegates," who have yet to throw their support behind a candidate.

"(They) might have to come into play to give somebody a 50 per cent majority at the convention," he said.