(CNN) -- Despite Sen. Barack Obama's commanding lead in the delegate count, Sen. Hillary Clinton campaigned hard Sunday, telling voters she's "running for the toughest job in the world."
Sen. Hillary Clinton has vowed to stay in the race until all states have a say.
Clinton spent her weekend in Kentucky, which, along with Oregon, holds its Democratic contest Tuesday.
Clinton is favored in Kentucky, while polls show Obama with a comfortable lead in Oregon.
Speaking in Bowling Green, the senator from New York said it was a "treat" to have the whole state to herself since Obama would not be returning there.
Clinton has faced calls to drop out of the race since she trails Obama across all fronts -- pledged delegates, superdelegates and the popular vote.
Clinton has recently been claiming a lead over Obama in the popular vote, a debatable claim, especially because the Democratic National Committee doesn't count the votes of Florida and Michigan, which Clinton does. Watch why she says she's ahead »
Florida and Michigan were stripped of their delegates for scheduling their primaries too early, and Clinton was the only top-tier candidate whose name was on the ballot in Michigan.
Clinton's campaign also excludes the caucus states in their popular vote count.
According to CNN's latest count, Obama leads Clinton in total delegates 1,904 to 1,717. A candidate needs 2,025 to clinch the Democratic nomination.
Clinton encouraged her Kentucky supporters to vote in the upcoming primary, saying Sunday, "If we get everybody turned out, it's going to send a great message to our country that you don't stop democracy in its tracks."
"You don't tell some states that they can't vote and other states that have already had the opportunity that they're somehow more important," she said.
In considering who to vote for, she told the crowd to "think about this as a hiring decision."
"Come out and vote for me on Tuesday, I'll work my heart out for you," she said.
Meanwhile Obama, who's been campaigning in Oregon, focused his attacks on Sen. John McCain, the presumptive Republican nominee.
Obama on Sunday suggested that McCain hasn't received the kind of scrutiny that he's received throughout the campaign.
"It is very understandable that the press focus has been on myself and Sen. Clinton because this has been a pretty exciting race on the Democratic side. I would expect that the press will submit him to the same scrutiny that they are submitting me," he said at a senior center in Gresham. Watch Obama speak in Oregon »
In Gresham, Obama detailed his plans to strengthen Social Security. Part of his plan includes eliminating income taxes for seniors making less than $50,000 per year.
Obama made low-key campaign stops this weekend, hitting a street festival in Keizer and stopping for ice cream in Eugene.
The last time Oregon had much weight in the primary season was in 1968, when Robert Kennedy was campaigning for the Democratic nomination.
The prolonged primary season comes to an end June 3. Puerto Rico weighs in on June 1, and South Dakota and Montana bring the season to a close the following Tuesday.
CNN's Jim Acosta, Suzanne Malveaux and Alexander Marquardt contributed to this report.