Hillary Rodham Clinton won a lopsided, but largely symbolic victory Sunday in Puerto Rico's presidential primary, the final act in a weekend of tumult that pushed Barack Obama tantalizingly close to the US Democratic presidential nomination.

The former first lady was winning roughly two-thirds of the votes.

In defeat, Obama was on track to gain at least 14 delegates, bringing him within 50 of the 2,118 needed for the nomination.

US Democratic presidential hopeful Sen. Hillary Rodham Clinton, D-N.Y., chats with supporters at the Kaslata Bakery in San Juan, as she campaigns on primary day in Puerto Rico, Sunday, June 1, 2008. [Agencies]

Aides predicted he could clinch the nomination as early as this week, when Montana and South Dakota close out the primary season, and he said he was confident the party would unite for the fall campaign.

"First of all, Senator Clinton is an outstanding public servant, she has worked tirelessly during this campaign ... and she is going to be a great asset when we go into November," he told an audience in Mitchell, S.D. "Whatever differences Senator Clinton and I may have, those differences pale in comparison to the other side."

Obama's confidence in the outcome of the historic battle for the nomination reflected the outcome of Saturday's meeting of the Democratic Party's rules and bylaws committee. Before an audience that jeered and cheered by turns, the panel voted to seat disputed delegations from Michigan and Florida, but give each delegate only one-half vote rather than the full vote sought by the Clinton campaign.

While the decision narrowed the gap between Clinton and Obama, it also erased the former first lady's last, best chance to change the course of the campaign.

With 57 percent of the precincts reporting, the Puerto Rico vote count showed Clinton with 131,304 votes, or 68 percent, to Obama's 61,614 votes, or 32 percent.

A telephone poll of likely Puerto Rican voters taken in the days leading up to the primary showed an electorate sympathetic to Clinton -- heavily Hispanic, as well as lower income and more than 50 percent female. About one-half also described themselves as conservative.

Nearly three-quarters of all those interviewed said they had a favorable view of Clinton, compared to 53 percent for Obama. One-third said they didn't know enough about Obama to form an impression.