There’s only one question: why Bernie Sanders’s attacking Hillary Clinton? The only aim of his dangerous game could be the helping to Donald Trump, and it’s obvious to everyone. Sanders and his wife look at Clinton and the Democrats as at Bernie’s real political enemies, not Trump/Republicans.
Bernie Sanders, however, has a dream to “arrive at the Philadelphia convention with maximum political power.” So, his recent strategy is to fight against Hillary Clinton” before the end of the primaries. Democrats’ real enemy, Trump, understands the power of misunderstandings within the Democrats, as well as advantages those given to him. Trump wrote on his Twitter: “Bernie Sanders is being treated very badly by the Democrats — the system is rigged against him. Many of his disenfranchised fans are for me!”
Clinton’s success is overwhelming to Sanders, his animosity toward Hillary would not matter so much if she were running against an extreme conservative e.g. Cruz, or even a conventional Republican like Mitt Romney. Actually, geography and demography heavily favor the Democrats, who have won the popular vote in five of the last six presidential elections.
And now, Sanders is out of the presidential race. Mass media cries out on Clinton’s success and her running against Trump. This dynamic game became too complex for Bernie Sanders, Trump is unpredictable and different, so Sanders decided just to help him.