Democratic presidential contenders Barack Obama and Hillary Clinton each won a primary on Tuesday, but the net result is that Obama is one step closer to securing his party's presidential nomination.  VOA National correspondent Jim Malone reports from Washington.

Most estimates now place Barack Obama within 100 delegates of the magic number of 2,026 he needs to claim the Democratic nomination outright.

Obama secured a majority of the pledged delegates after his victory in the Oregon primary.  Pledged delegates are awarded on the basis of the caucus and primary contests that began with Obama's victory in Iowa on January 3.

Obama was back in Iowa Tuesday night and spoke optimistically about unifying the Democratic Party once his race with rival Hillary Clinton is over.

"Some may see the millions of votes cast for each of us as evidence that our party is divided," he said.  "But I see it as proof as we have never been more energized and united in our desire to take this country in a new direction."

For her part, Clinton won another convincing victory in Kentucky.  Clinton will remain in the race through the end of the primary season on June 3 and continues to insist that she would be the stronger Democrat to run against the presumptive Republican nominee, Senator John McCain.

"Our party will have a tough choice to make, who is ready to lead our party at the top of our ticket?" she asked.  "Who is ready to defeat Senator McCain in the swing states and among swing voters?"

Clinton easily outpaced Obama among white working class voters in Kentucky, something she has done in several recent primaries.  Obama improved his showing among working class voters in Oregon.

Contrary to Clinton's view, Oregon voters also saw Obama as the stronger opponent for McCain in the general election.

Anthony Salvanto is director of surveys for CBS News.

"In winning Oregon, Barack Obama was seen as the candidate best able to defeat John McCain in the fall," he noted.  "By about a two to one margin, Oregonians said that it was Obama, not Clinton, who would be the one best able to defeat McCain."

Experts see no way for Clinton to catch up to Obama in the overall delegate count between now and the end of the primaries on June 3.  Clinton's only path is to convince a large number of the 200 or so remaining uncommitted superdelegates that she would be a stronger nominee than Obama, despite his lead in the delegate count, popular vote and number of states won.

Superdelegates are Democratic officeholders and party activists free to support either candidate.  But more of them have been flocking to Obama in recent weeks than to Clinton.

Tom DeFrank of the New York Daily News says Clinton supporters are adamant that she stay in the nomination race until the end.

"And I think she also feels, some of her friends say, that she feels real obligations to the tens of thousands of people, especially women voters, who have stuck with her and would like her to see it through to the end," he said.

Some Democratic Party leaders are already looking ahead to how the party can bind up the wounds after a long and bruising nomination fight.  Former Democratic Senate leader Tom Daschle is an Obama supporter who made an appeal for unity on CBS television.

"We want to begin the process of bringing this party together, and I think over the last few weeks we have seen indications at virtually all levels in both campaigns that there is a desire to do that," he explained.

Only three more primaries remain in the Democratic contest.  Puerto Rico votes on June 1, followed by South Dakota and Montana on June 3.  Many senior Democrats expect the party to rally around Obama as the presumptive nominee sometime in June, well before the Democratic nominating convention in late August.