Hillary Rodham Clinton won the Kentucky primary on May 20, a victory of scant political value in a Democratic presidential race moving inexorably in Barack Obama's direction.

The two rivals also collided in Oregon's unique vote-by-mail contest, and Obama predicted he would finish the night with a majority of all delegates at stake in the 56 primaries and caucuses on the campaign calendar.

With votes counted from 41 percent of the Kentucky precincts, Clinton was gaining 57 percent support, compared with 40 percent for Obama.

Interviews with Kentucky voters leaving their polling places showed Clinton's victory was roughly as sweeping as the rout she fashioned last week in West Virginia.

Almost nine in 10 ballots were cast by whites, and the former first lady was winning their support overwhelmingly.

She defeated her rival among voters of all age groups and incomes, the college educated and non-college educated, self-described liberals, moderates and conservatives.

Though Clinton has had a strong run through the late primaries, Obama has steadily outpaced her where it counts, in the race for national convention delegates.

With her Kentucky victory, Clinton picked up at least 27 delegates, with an additional 24 to be awarded.

Overall, Obama had 1,917 delegates, little more than 100 shy of the 2,026 needed to become the first black presidential nominee of a major party. The former first lady had 1,749.

Regardless of the results of the night's two primaries, Obama decided to mark a victory of sorts.

He arranged an evening appearance in Iowa, site of his critical Jan. 3 caucus triumph that launched him on his way through the primaries that followed.

"The question then becomes how do we complete the nomination process so that we have the majority of the total number of delegates, including superdelegates, to be able to say this thing's over," Obama told The Associated Press in an interview.