Barack Obama's Appalachia problem couldn't be more apparent in a new Rasmussen poll, with Hillary Clinton winning Kentucky in the general election, and Obama losing it in a landslide:

McCain (R) 57%, Obama (D) 32%
Clinton (D) 51%, McCain (R) 42%

Sample size: 500 likely voters.
Margin of error: ±4%

Obama has done well among white voters in many other parts of the country, but the Appalachian region has become something of a no man's land for him. And with that region spanning a lot of electoral votes, this poll definitely gives some weight to Hillary Clinton's arguments on electability.

All the networks call Kentucky for Hillary, seconds after the polls close. The exit polls suggest a two-to-one margin.

More from the exits:

Only 33 percent of Hillary backers in the state say they'd vote for Obama in the general election.

Of course, Kentucky's electorate is among the most conservative: Only a third of voters called themselves liberal.

Late Update: With nearly a third reporting, Hillary is leading Obama by nearly 20 points, 58%-39%.

This is a big day for the presidential campaign, with the primaries in Oregon and Kentucky practically guaranteed to clinch a majority of pledged delegates for Barack Obama.

Polls in Kentucky show Clinton on track for a two to one win in Kentucky, as she has performed best against Obama in the Appalachian region. Obama, meanwhile, is favored to win Oregon by a strong margin. Kentucky has 51 pledged delegates, and Oregon has 52 -- and with Obama only needing less than 20 delegates to clinch the pledged majority, he'll get more than he needs to reach that goal.

The question then becomes how the two camps spin the results, and whether the Obama camp plays it up as a genuine victory mark for the campaign. Obama himself has said he won't, but the Hillary camp has already been pre-rebutting that idea, calling it a "slap in the face" to the millions of people who have voted for her.

The first polls close at 6 p.m. ET in Kentucky, followed by western Kentucky at 7 p.m. ET. Oregon's mail-in voting ends at 11 p.m. ET.

Although Barack Obama is on his way to clinching a majority of pledged delegates tomorrow, a new round of polls from Suffolk University shows that it might not be by much on the day it actually happens.

Obama is headed for a landslide loss tomorrow in Kentucky, while it could be a close race in Oregon, where he's favored:

Kentucky
Clinton 51%
Obama 25%

Sample size: 600 likely primary voters.
Margin of error: ±4%

Oregon
Obama 45%
Clinton 41%

Sample size: 600 likely primary voters.
Margin of error: ±4%

Obama's popularity varies immensely between states -- he's viewed favorably by only 43% of Democratic respondents in Kentucky, and by 73% of respondents in Oregon.

In a further sign that Barack Obama is looking past the primary season and onward to the general election, the Obama campaign has announced that he'll be spending Tuesday night not in Oregon or Kentucky -- where primaries will be held that day -- but in Iowa.

The Obama campaign is very likely to clinch an overall majority of pledged delegates with Tuesday's contests, so the symbolism of his swing-state rally should be obvious: That he considers himself the popularly-elected nominee, and the race is on to fight John McCain.

Hillary Clinton's campaign has yet to announce where she will be on Tuesday.

Barack Obama now has a new ad in Kentucky, a state where he isn't expected to do at all well in the May 20 primary -- a possible effort to dispel the idea that he can't compete in rural areas.

The ad features a southern Illinois coal worker taking about Obama's commitment to coal technology:

The ad seems to be formulated to deal with a critique of Obama that has surfaced in the last few contests: That in the wake of the "small town" comments, he has trouble relating to or connecting with rural voters.

Interestingly, Ben Smith notes that the Obama camp hasn't blasted this ad to reporters in the way they usually do -- perhaps because liquid coal technologies aren't particularly popular with environmental activists.

Barack Obama is set to pick up a major endorsement in Kentucky today, with the campaign saying Congressman Ben Chandler will announce his support at a news conference this afternoon in Louisville.

Along with freshman Rep. John Yarmuth, who endorsed back in February, Obama now has the support of both of Kentucky's Democratic House members -- which is odd considering that Kentucky may well be his single worst state in the Union in both primary and general election polls, and thus it doesn't seem like he'd be much help to them at the top of the ticket.

Barack Obama has this new ad running in Kentucky, a stock ad he's long used to promote his work on ethics reform and his independence from special interests in Washington:

Kentucky may very well be Obama's worst state in the country, both in terms of how he polls against Hillary Clinton in the primary and against John McCain for the general election. So for him to be running an ad here shows the degree to which his campaign is leaving no stone unturned in using their big cash advantage over Hillary Clinton.

The first poll of the Kentucky Democratic primary confirms everyone's suspicion that this state is set to go to Hillary Clinton in a big way. The numbers from SurveyUSA: Clinton 58%, Obama 29%.

The Kentucky primary will be held on May 20 — the same day as the primary in Oregon, where Obama is expected to win.

A new set of polls by SurveyUSA shows that Barack Obama's electability has taken a serious drubbing as a result of his recent setbacks, and he now does much poorer than Hillary Clinton does against John McCain in the three tested states:

Ohio
Clinton (D) 50%, McCain (R) 44%
McCain (R) 50%, Obama (D) 43%

Missouri
McCain (R) 48%, Clinton (D) 46%
McCain (R) 53%, Obama (D) 39%

Kentucky
McCain (R) 53%, Clinton (D) 43%
McCain (R) 64%, Obama (D) 28%

The internals show that in all three cases Obama gets a smaller share of the white vote than Hillary does, without room for his improvements among African-Americans to make up the difference.

(Via MyDD)

Late Update: One thing also worth noting is that these polls were conducted before Obama's speech yesterday on race relations, so we simply don't know yet what impact it might have in turning these numbers around.

A new SurveyUSA poll of Kentucky shows Hillary Clinton beating the Republicans in all four match-ups, with two results within the margin of error and two well beyond it. On the other hand, Barack Obama doesn't do nearly as well, losing three matched and holding only a statistically insignificant lead in the other:

Clinton (D) 48%, Giuliani (R) 44%
Clinton (D) 54%, Romney (R) 39%
Clinton (D) 55%, Huckabee (R) 36%
Clinton (D) 48%, McCain (R) 47%
Giuliani (R) 52%, Obama (D) 38%
Romney (R) 44%, Obama (D) 43%
Obama (D) 44%, Huckabee (R) 42%
McCain (R) 56%, Obama (D) 34%

A new SurveyUSA poll shows Hillary Clinton running a close race against the top four Republicans:

Clinton (D) 47%, Giuliani (R) 45%
Thompson (R) 47%, Clinton (D) 45%
Clinton (D) 50%, Romney (R) 41%
Clinton (D) 49%, Huckabee (R) 39%
McCain (R) 49%, Clinton (D) 45%
Clinton (D) 51%, Paul (R) 35%
Gore (D) 46%, Giuliani (R) 45%

President Bush easily carried Kentucky in both 2000 and 2004, but the state also voted for Bill Clinton twice.