LOUISVILLE, Ky. -- Sen. Barack Obama won the Oregon Democratic primary election Tuesday night and moved to within 100 delegates of the total needed to claim the prize at the party's national convention this summer, even as his rival, Sen. Hillary Rodham Clinton, claimed victory in the Democratic race in Kentucky.

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"Tonight, in the fullness of spring, with the help of those who stood up from Portland to Louisville, we have returned to Iowa with a majority of delegates elected by the American people and you have put us within reach of the Democratic nomination for president of the United States of America," he told cheering supporters in Iowa.

The overwhelmingly white state launched him on his improbable path last January. If he wins the nomination, he will be the first black man from a major political party to run for the White House in the general election.

While all but claiming ultimate victory, Obama lavished praise on Clinton, calling her a historic figure as she seeks to be the first woman nominated to run for president by a major political party.

"We have had our disagreements during this campaign, but we all admire her courage, her commitment and her perseverance," Obama said. "No matter how this primary ends, Sen. Clinton has shattered myths and broken barriers and changed the America in which my daughters and yours will come of age."

Then, he called for party unity, even as he reached out to disaffected Republicans and independents.

"You are Democrats who are tired of being divided, Republicans who no longer recognize the party that runs Washington, independents who are hungry for change," he said, speaking to a crowd on the grounds of the Iowa Capitol in Des Moines as well as the millions around the country who will elect the nation's 44th president in November.

Clinton, meanwhile, vowed to fight on for her party's nomination in the face of increasingly narrow odds against Obama, and cast herself as the best candidate for the general election.

"We have to select a nominee who is best positioned to win in November," said Clinton at a victory rally in Louisville. "You know the stakes are high."

"We are in this race because we believe it will take a commander in chief with the strength and knowledge to end the war in Iraq, safely and quickly, and a president with experience, representing the people of the United States in more than 80 countries, to restore our leadership and moral authority in the world," she said.

Thanking Kentucky for an "overwhelming vote of confidence, even in the face of some pretty tough odds," Clinton told her supporters that "this is one of the closest races for a party's nomination in modern history."

Despite losing Kentucky to Clinton by a margin of 65 percent to 30 percent, Obama picked up at least 14 delegates in the state. That gave him 1,931 out of the 2,026 needed. The former first lady has 1,755 in their marathon race -- a black man running against a woman -- that has shattered voter turnout records in state after state.

Clinton won at least 37 delegates in the two states and Obama won at least 23, according to an analysis of election returns by The Associated Press. All the Kentucky delegates were awarded, but there were still 43 to be allocated in Oregon, and Obama was in line for many of them.

He had 1,940 delegates overall, out of 2026 needed for the nomination. Clinton had 1,759 according the latest tally by the AP.

With about 30 percent of the votes counted in Oregon's unique mail-in primary, Obama was gaining a 60 percent share to 40 percent for Clinton.

Turning attention away from Clinton, Obama warned of a tough campaign ahead against the Republicans and Arizona Sen. John McCain, their expected presidential nominee. And he lumped them together in a laundry list of what he called failed policies, from the war in Iraq to health care and the economy.

"I will leave it up to Sen. McCain to explain to the American people whether his policies and positions represent long-held convictions or Washington calculations," Obama said. "But the one thing they don’t represent is change."

"The other side knows they have embraced yesterday’s policies and so they will also embrace yesterday’s tactics to try and change the subject," he said. "They will play on our fears and our doubts and our divisions to distract us from what matters to you and your future. Well they can take the low road if they want, but it will not lead this country to a better place. And it will not work in this election. It won’t work because you won’t let it. Not this time. Not this year."

Race, Education Factor In Exit Polls

The former first lady's 65 percent to 30 percent Kentucky victory -- and the exit polls -- underscored once more the work Obama has ahead if he is to win over her voters.

Kentucky had one of the least liberal electorates out of 33 competitive Democratic primaries in which exit polls were conducted this year -- only about a third of voters called themselves liberal. In contrast, Oregon was among the most liberal Democratic electorates to date, with close to six in 10 voters in the state's vote-by-mail primary calling themselves liberal. In most primaries to date, Clinton has done better with more conservative voters, while Obama has done better with those who are more liberal.

Kentucky continued a recent trend in Democratic primaries with voters overwhelmingly picking the economy when given three choices for the most important issue facing the country. Oregon defied that trend. About two-thirds of Democratic voters in Kentucky said the economy was the top issue, about 20 percent picked the Iraq war and half as many said health care. In Oregon, fewer than half picked the economy, three in 10 said Iraq and two in 10 said health care.

Voters in Kentucky were quite a bit more likely than in Oregon to say the current recession or economic slowdown has affected them and their families a great deal. Kentucky Democrats also were more likely than their Oregon counterparts to say it's a good idea to suspend the federal gas tax this summer - an idea Clinton has promoted and Obama has criticized.

As Obama has built a daunting lead among convention delegates, his own supporters in both Kentucky and Oregon were nearly unanimous in thinking he will secure the Democratic nomination. Many Clinton voters maintained hope for their candidate but substantial numbers acknowledged Obama as the likely nominee - half of Clinton voters in Oregon and a third in Kentucky said Obama will win the nomination.

All balloting was by mail in Oregon's primary and the phone poll asked when people voted or planned to. The survey found Clinton ran stronger among those who voted earlier while Obama ran better among those who mailed or delivered their ballots closer to Election Day.

In Kentucky, three in four voters said they made up their minds more than a month ago.

Nearly two in 10 Kentucky Democratic voters said John Edwards' endorsement of Barack Obama was a very important factor in their vote and nearly three in 10 said it was somewhat important. The question wasn't asked in Oregon, where the phone poll began before Edwards announced his choice.

As usual for this Democratic primary season, Clinton tended to run better in both states among older voters, those with lower income and less education, and those in rural areas, while Obama strengths included the young, urban, wealthier and better educated voters.