he could endorse a candidate with a more similar view of politics maybe? There are plenty independents candidates that could do with the endorsement of Bernie, candidates that think like him.
if he does that, then you know the man is a man of hos word, a man of honor.
But instead, he goes back to the very origin of the problem, and supports a shitty candidate from the old Bipartisan politic system that is corrupted as feck.
There's a reason he is endorsing Hillary - because without his support Trump will be the next President. There is no such thing as a legitimate third party option in this race that wouldn't result in either Hillary or Trump getting elected. Policy wise, Bernie and Hillary are pretty much in sync if you compare their platforms to Trump's.