However, the contests, collectively known as the "Potomac Primary," will not be the coronation moment for the first-term black senator.

    Results of the races will give him an undisputed lead among pledged delegates to the Democratic national convention in August.

    Together his victories over the weekend, such a sweep will also bestow unmistakable momentum heading toward next week's primary in Wisconsin and caucuses in Hawaii.

    After Tuesday's contests, Obama will very likely lead Clinton in the number of delegates.

    Currently, he and Clinton each have 1,121 and 1,148 delegates based on CNN's tally.

    He leads Clinton in the number of pledged delegates 986 to 924,but trails her in the tally of super-delegates 135 to 224.

    When the Potomac Primary is over, Obama will very likely have an overall lead.

    Even though, the Democratic race is still far from ending since it needs at least 2,025 delegates to secure the party nomination and neither of them is likely to reach that number in a short period.

    Many experts said Obama may not be able to claim the status of front-runner until Ohio and Texas primaries on March 4 or even the Pennsylvania primary on April 22.

    Clinton's recent losses mean she needs a circuit breaker before March 4 -- perhaps the two debates scheduled the week before Ohio and Texas offer that opportunity -- to change the dynamic of the race.

    Super-delegates

    Given the tight nature of the Democratic race, many agree that it will largely be up to the 796 unelected super-delegates to decide the nomination.

    About half of the super-delegates are still uncommitted.

    Clinton now has an advantage among the super-delegates.

    However, her money problems and staff shake-up may rattle some super-delegates who had assumed at the start of this campaign that she had the superior fundraising capacity and a seasoned team that could weather unexpected problems.

    Republican consultant Mike Murphy said that if Obama sweeps contests Tuesday and then wins Ohio, Texas or both, then "it'll be a combination of true enthusiasm for Obama and the old pol's rule of 'be for what is going to happen.'"

    McCain's gain

    The undecided Democratic battle could benefit the presumptive Republican nominee, Sen. John McCain.

    Simply put, as Clinton and Obama continue at a punishing pace, McCain can relax and recharge.

    Moreover, McCain will be able to campaign solely against the Democrats, beginning a general election argument long before Clinton or Obama can.

    The money he raises between now and the convention can be put to that purpose as well.

    He can start to unify the GOP -- not a moment too soon, in his case -- and begin to build a general-election field organization.

Profiles: U.S. 2008 presidential primaries, caucuses forerunners

Backgrounder: Key players in 2008 U.S. presidential race

Backgrounder: U.S. presidential nomination process and Iowa caucus

Backgrounder: Major events leading up to 2008 U.S. presidential race

Calender: U.S. 2008 presidential primary, caucus