Here's how rough the math is for Sanders going forward: To win a majority in pledged delegates, he needs to win 58 percent of those remaining.
That might not sound so bad. But because all the Democratic contests allot their delegates proportionally, it's actually punishingly difficult.
It means Sanders has to beat Clinton by around 58 percent to 42 percent pretty much constantly. And that's just incredibly implausible given what's happened so far, and especially given what's happened tonight.
Even unexpected wins for Sanders in big states like California, New York, Pennsylvania, and New Jersey — already unlikely — wouldn't be enough. Sanders has to win those states by enormous margins.
And there are still a great deal of delegates left in states and territories with large nonwhite populations — states with demographics similar to those that have favored Clinton so far. These include Maryland, Arizona, New Mexico, and even Puerto Rico (which Clinton won in a blowout in 2008).
Plus,
any further Clinton victory just makes the targets Sanders has to hit even more absurd. At this point, the only thing Sanders can really hope for is that some scandal emerges that tanks Clinton's numbers everywhere.
http://www.vox.com/2016/3/15/11243398/bernie-sanders-election-results-2016-winning
That last sentence explains why there is this relentless banging of the same old 'Hillary bad candidate' drums is coming daily from the Bernie supporters. They know that they need something horrible to stick to Hillary in order for their guy to win.
It's sort of the same way (in my opinion) a horrible terrorist attack on Obama's watch might be the only way for Trump to beat the Democrat in the Fall.