In the next hour, we'll start to see results from Kentucky, with Oregon a bit less than 6 hours away. While it's now clear that Hillary will stay in for the last three primaries ending June 3, and for the DNC Rules Committee meeting on May 31 that will decide the fate of Michigan and Florida delegations, Obama will almost certainly have gained a majority of pledged delegates, whether you count all states excluding MI and FL or, likely, even if you include them. No one from the Obama camp, or from the Democratic powers that be will tell Hillary to step down until after June 3, but Hillary will lose all credibility if she doesn't concede shortly after the last primary.
In Kentucky, don't be fooled by early returns, which will start rolling in around 3:30 Pacific Time. Because of the time zone split in Kentucky, early results will mostly reflect returns from Louisville in the eastern half of the state. Western Kentucky is demographically pretty similar to West Virginia, so when those returns get factored, Obama will be lucky to crack 30%. Kentucky polling has been remarkably consistent at showing Hillary performing in the low-60s. The rest goes to Edwards, who as in WV remains on the ballot, and "Uncommitted," which is actually an option on the Kentucky ballot.
In Oregon's all-mail balloting, ballots have to be turned in by 8pm. Counting actually started this morning. So, we'll know the first results, mostly from the heavily Obama-favored Portland area right at 8pm PDT. Those early results are likely to get watered down a bit (or maybe not), but expect the final results to give Obama somewhere between 54 and 64% of the vote.
If all goes as expected, the meme that will enshroud the airwaves and print media is that it's all over, Obama is the nominee no matter what happens with FL and MI, but the Kentucky results show that Obama continues to have troubles gaining the vote of working-class whites (conveniently ignoring the fact that OR is almost as blue collar as KY and probably whiter). But, if all goes expected tonight, or if it's any better than expected, Obama may well get the superdelegates he needs to declare victory on June 3, or even earlier.