Let's breakdown the math before June 7th and on June 7th

[Godhumor]

Per RCP, Sanders is currently 283 pledged delegates behind.

Before the big June 7th day there are only 183 delegates up for grabs between OR, KY, VI and PR. To get to 200 behind by the end of that stretch, Sanders needs to win 72.7% of all pledged delegates in the next 4 races (133 of 183).

Let's pretend he can do that. There is total of 694 pledged delegates on June 7th between CA, NJ, ND, SD, MT and NM. To make up that wildly unlikely 200 point gap, Bernie needs to win 64.4% of the delegates on this date (447 of 694) just to tie Clinton.

That's brutally unlikely.

Except just one last thing.

DC votes on June 14th. DC has 20 pledged delegates. DC is over 50% black.

So that brutally unlikely hypothetical I laid out above? It still ends in a Clinton pledged delegate victory.

[still_one]

1. and because Democrats award delegates proportionally, it makes it even more formidable

[Recursion]

2. DC is black-plurality, not black-majority, incidentally

There was a lot of hand-wringing and gnashing of teeth when that line was crossed a few years ago.

[Godhumor]

3. I believe it was at 49% based on 2015 numbers

So I'm comfortable keeping it at half black in the OP. It would make no difference in the results of the primary.

[thesquanderer]

4. Here's a possible path I came up with

Yes, I'll admit, it's unlikely in the extreme. But not absolutely impossible.

http://demrace.com/?share=GH4zWRsT

(It gives Hillary close wins in New Jersey, New Mexico, and DC while giving Bernie all the rest, mostly at margins of 65 to 72)

It's a fun site to play with. It also does inject a dose of realism, as you say just how hard it is to come up with even barely plausible scenarios for Bernie. Really, it's hard to imagine Bernie getting some of those numbers short of a damaging announcement by the FBI/DOJ. And possibly even then.

[1939]

5. Kay, this pretty much says it all

http://www.bostonglobe.com/opinion/2016/03/24/editorial-cartoons-dan-wasserman/53FICoEDwqus1gkC3jdurK/picture.html

[NurseJackie]

6. Oh, you and your math! Always crushing dreams and fantasies! Ya big ol' meanie!