Barack Obama and Hillary Rodham Clinton heaved toward the finish line in their exhaustive Democratic presidential odyssey with Obama poised to claim victory and Clinton facing the prospects of having to abandon a quest that once seemed a sure shot but became one of long odds.
And although Tuesday's primary-season ending contests in South Dakota and Montana won't decide the Democratic nomination, the closing of the polls could open the floodgates to dozens of superdelegates — members of Congress and other party leaders — long anxious to throw their support to Obama.
That could decide the nomination in a matter of days.
Hillary Rodham Clinton won a lopsided, but largely symbolic victory in Puerto Rico's presidential primary, the final act in a weekend of tumult that pushed Barack Obama tantalizingly close to the Democratic presidential nomination.
The former first lady was winning roughly two-thirds of the votes as she continued a strong run through the late primaries.
As Barack Obama turns to concentrate on his general election challenge, his rival Hillary Rodham Clinton is mounting a last ditch campaign to stay relevant in what is left of the Democratic presidential contest.
The former first lady enters this week with an insurgent strategy not only to win over undecided superdelegates but to peel away Obama's support from those party leaders and elected officials who already have committed to back him for the nomination.
"One thing about superdelegates is that they can change their minds," she told reporters aboard her campaign plane Sunday night.
Democratic Party leaders agreed Saturday seat Michigan and Florida delegates with half votes into this summer's convention with a compromise that left Barack Obama on the verge of the nomination but riled Hillary Rodham Clinton backers who threatened to fight to the August convention.
"Hijacking four delegates is not a good way to start down the path of party unity," said adviser Harold Ickes.
Clinton's camp maintains she was entitled to four additional Michigan delegates.
Barack Obama said Saturday he has resigned his 20-year membership in the Trinity United Church of Christ in Chicago "with some sadness" in the aftermath of inflammatory remarks by his longtime pastor, the Rev. Jeremiah Wright, and more recent fiery remarks at the church by a visiting priest.
"This is not a decision I come to lightly ... and it is one I make with some sadness," Obama said at a news conference after campaign officials released a letter of resignation he sent to the church on Friday.
Unlike Hillary Rodham Clinton, rival Barack Obama planned for the long haul.
Clinton hinged her whole campaign on an early knockout blow on Super Tuesday, while Obama's staff researched congressional districts in states with primaries that were months away. What they found were opportunities to win delegates, even in states they would eventually lose.
The fate of nearly 2.3 million Democratic presidential primary votes belongs to 30 party activists.
The activists sit on the Democratic Party's Rules and Bylaws Committee, which was to meet Saturday to decide what role Michigan and Florida should play at the national convention in August.
Top Democratic leaders intend to push for a quick end to the battle for the presidential nomination when primaries are over next week, Senate Majority Leader Harry Reid said Thursday, adding that he, Speaker Nancy Pelosi and party chairman Howard Dean will urge uncommitted delegates to choose sides.
"By this time next week, it will all be over give or take a day," Reid said of the marathon race between the front-running Barack Obama and Hillary Rodham Clinton.
Obama is within 44 delegates of clinching the nomination, according to The Associated Press tally, and leads Clinton by roughly 200 delegates.
Hillary Clinton says she's still in it to win it.
Although pundits and political observers say there's almost no way she can wrest the Democratic presidential nomination from Barack Obama, Clinton is still campaigning. She even raised controversy recently when she invoked the June 1968 assassination of Robert F. Kennedy to note that previous nominating campaigns extended into the summer.
Democratic presidential candidate Barack Obama said Thursday that he was "deeply disappointed" by a supporter's sermon at his church that mocked Hillary Rodham Clinton.
The Rev. Michael Pfleger, a Chicago activist, also apologized for last Sunday's sermon at Obama's church, in which he said Clinton's eyes welled with tears before the New Hampshire primary because she felt "entitled" to the Democratic nomination and because "there's a black man stealing my show."