U.S. Senator Hillary Clinton has won Sunday's Democratic presidential primary contest in the commonwealth territory of Puerto Rico, soundly defeating rival Senator Barack Obama by a two to one margin. VOA's Michael Bowman reports, the Clinton victory comes near the end of the U.S. presidential primary season, and will only slightly erode Obama's lead among party delegates that will determine the Democratic presidential nominee.

Conventional wisdom holds that, at this point, Hillary Clinton has only the faintest hopes of securing the Democratic nomination. Nevertheless, she is finishing the primary season on a strong note. In recent weeks, she has scored overwhelming victories in the states of West Virginia and Kentucky. Now, she adds Puerto Rico to her win column.

Exit polls in the island territory showed her winning among all age groups, and among both men and women. Puerto Ricans may vote in primary contests, but not in the presidential election in November.

Obama still holds a comfortable lead among party delegates accrued from states and territories that have held primaries and caucuses since the beginning of the year. But Clinton's recent victories have, by some calculations, put her ahead in the popular vote tally of all ballots cast in the primary season to date.

Clinton highlighted her popular vote totals in a victory speech to supporters in Puerto Rico.

"More people have voted for us than for any candidate in the history of presidential primaries," said Hillary Clinton. "We are winning the popular vote. And it is important where we have won. We are winning these votes in swing states and among the very swing voters [that] Democrats must win to take back the White House."

Clinton added that so-called "super delegates" - party elders and elected officials who may endorse any candidate - will ultimately decide who becomes the Democratic presidential nominee. She urged super delegates to pick the strongest candidate to go up against Republican John McCain in November, and said she is that candidate.

But the Obama campaign counters that Clinton's popular vote argument is flawed, since it does not take into account vote tallies from many caucus states. Furthermore, Democratic Party rules do not mention the popular vote as a criterion for determining a presidential nominee, a point made by Obama campaign spokesman Robert Gibbs on ABC's "This Week" program:

"The nomination is decided by the number of delegates that you have, and I think that the winner of the majority of those delegates will soon be Senator Obama," said Robert Gibbs.

Saturday, Clinton picked up two dozen delegates when the Democratic Party reinstated primary votes from Florida and Michigan. Those states had been stripped of their delegates after moving up their primary dates in violation of party rules. The party opted to count each delegate from those states as a one-half vote.

After the Puerto Rico primary, Obama stands less than 50 delegates away from clinching the nomination, with just two states - Montana and South Dakota - left to vote. There are more than 150 super delegates who have yet to endorse either candidate. Party leaders are pressuring all remaining super delegates to make their preference known after the final primaries this Tuesday. Should they do so, the Democratic presidential nominee will likely be known sometime this week.