Obama Wins in Oregon and Clinton Prevails in Kentucky

Clinton's win in Kentucky is unlikely to change that dynamic. Polling showed Clinton with a wide lead and Obama's campaign had largely conceded the state to the New York Senator.

Oregon seems to be friendly territory for Obama. He enjoys support in a series of college town along the state's western coast, as well as in the progressive bastion of Portland. About 80,000 people gathered at a rally in Portland over the weekend to hear Obama speak.

At stake in today's voting are 51 pledged delegates in Kentucky and 52 in Oregon. Only Democrats are eligible to vote in each primary.

Polling places opened at 6 a.m. EDT and were scheduled to close at 7 p.m. eastern time in Kentucky. Polls in Oregon opened at 7 a.m. Pacific time in most of the state and were closing at 8 p.m.

Oregon is a vote-by-mail state and ballots were first sent out on May 1. More than 800,000 ballots had already been cast as of Monday and state election officials believe another 250,000 will be dropped off at polling places today.

After tonight, just three nominating contests remain. Puerto Rico will vote on June 1 while South Dakota and Montana will bring the race to a close on June 3. None of the remaining contests are expected to alter the math of the Democratic nomination, which is close to determinative in Obama's favor.

A candidates needs a total of 2,026 delegates to secure the nomination. Obama leads Clinton in total delegates -- pledged and super -- 1905.5 to 1723.5. He also holds a 16,157,639 to 15,583,020 popular vote lead over Clinton, according to NBC's political unit.

As of today, slightly more than 200 superdelegates have not stated which candidate they support. Clinton continues to assert that she can attract considerable support among the undeclared superdelegates, but the trend of late has been to Obama, not Clinton.

Staff writers Perry Bacon Jr. and William Branigin contributed to this report