He cooled it on the personal attacks, but used every bit of leverage he had to move both Hillary and the Democratic platform to the left. He didn't get everything he wanted ... he never expected to. He did lose the primary, after all.
Nonetheless, he got a helluva lot. He played his cards well, and in Hillary Clinton I think he had a fairly willing sparring partner. She didn't fight all that hard against his platform demands.
[Y]esterday the platform was finished, and Bernie is pretty happy with it. With that done, he's endorsing Hillary almost immediately. ...[H]e stopped the personal attacks, pushed the party to the left, and now he's diving in to the campaign against Donald Trump. Good work.
Bernie Sanders has been in politics a long time, usually working from a position of weakness, and knows when to hold 'em and when to fold 'em. I was baffled by the hysterical nature of the attacks on him by the Clintonistas, because it seemed clear to me that all Sanders was doing was trying to maximize his leverage. You don't do that by folding early. And he is still trying to maximize his leverage, which is why he'll be working with Clinton now.