LOUISVILLE, Ky. (AP) _ Barack Obama is reaching for a symbolic tipping point in the Oregon and Kentucky primaries Tuesday — a majority of pledged delegates offered in the Democratic presidential contest.

Hillary Rodham Clinton vowed there was "no way that this is going to end anytime soon" as she campaigned Monday across Kentucky, a state she was expected to win.

Obama was favored in Oregon, where supporters delivered the largest crowd of his campaign on Sunday.

Regardless of who prevails in those states, Obama is on track to secure the largest share of delegates who could be won in the long slog of primaries and caucuses since the snows of January.

If there were to be practical dividends in that achievement, they would come from persuading the remaining uncommitted superdelegates — the party insiders who are not tied to primary or caucus results — to pick up the pace of their endorsements.

Enough of them have done so already to transform Clinton's hopes for the nomination from improbable in recent weeks to worse.

Still, the New York senator soldiered on through event after event, ending her night Monday in Louisville before a crowd of several hundred, her voice raspy from the stage.

"There are a lot of people who wanted to end this election before you had a chance to vote," she said, husband and former President Clinton at her side. "I'm ready to go to bat for you if you'll come out and vote for me."

She argued at one stop that she is the "more progressive candidate" and dismissed Obama's large crowds, like the record rally by an estimated 75,000 in Portland on Sunday.

Clinton said Obama, who has refused to debate her since before the Pennsylvania primary last month, would "rather just talk to giant crowds than have questions asked."

Obama planned to spend the latest primary day in Iowa, the state of his opening electoral success. This, after he campaigned Monday in Montana, where voters will join those from South Dakota on June 3 in dropping the curtain on the 2008 primary and caucus season.

The Illinois senator rarely mentions Clinton now, except to praise her "magnificent" campaign — praise he can now afford to give his rival. He is tangling almost solely with Republican John McCain in a prelude to the fall general campaign.

A look at some of the numbers at play going into Tuesday's contests:

—Obama was 17 delegates short of reaching a majority of the 3,253 pledged delegates available in all state contests.

—Oregon offered 52 delegates; Kentucky had 51.