So we now have to acclimate to front-runner Bernie. Whatever. If Bernie is the nominee, unless he starts blaming groups of people for our problems other than the rich and perhaps the Religious Right, I will support him to the letter of the crossed t and you would never have known that I ever hated him. Even if there's a Michael Bloomberg third-party candidacy (and if Bernie wins the nomination, there very well might be), I will support any Democratic nominee to the bitter end who doesn't scapegoat anybody but the relatively more privileged, and that end will probably be bitter indeed.
Bernie's policies are mostly fine, insofar as they have any nuance at all, I agree with 80-90% of them, and many of them are closer to my beliefs than they are to his most fervent admirers, who are well to the left of his campaign. If Bernie appears to have a chance of winning right now, that appearance is very deceptive. Once the battalion of dubious quotes and interviews appear all over the media of Bernie's support of America's enemies, every swing voter who is mulling a Bernie vote will be scared away, the tragic irony being that no American President has ever gone further into the arms of America's enemies than our current President - it's not even close, but no amount of Democratic spending will be able to countermand the private PAC-money of billionaires whom Bernie correctly points out are choking the American system, and they will bombard American mental space into submission to their agenda.
And even if Bernie were able to keep himself in swing voter's warm feelings, what then? There remains the problem of a Bloomberg Third Party Candidacy. Look at your TV, look at youtube. Bloomberg is not at any debate, but he's bombarding the airwaves unceasingly, and is spending more on TV than all the other Democratic candidates put together (that's true, look it up). Why is that? He's clearly gearing up for a third party run. If it's Biden, he obviously won't do it. If it's Warren, he might do it, but he might not, and he knows that it's sensible not to, and his whole campaign is based on doing the sensible thing. But if it's Bernie, he probably will because he knows there's a path to victory through the American center, who is rightly disgusted by Trump and perhaps wrongly disgusted by Bernie Sanders.
And even if the impossible happened, and Bernie won, what then? A Republican congress accusing him of being a traitor to the American people? There's literally an interview circulating around the internet of Bernie on Cuban Television in the 80s, criticizing America and praising Castro. That's probably one of a dozen like it from that era. Everything we've correctly accused Trump of, they will accuse Bernie of. Even if we have the House now, we will lose it in 2022 with a Bernie presidency. They will impeach him, and they will have the votes in the Senate to remove him from office.
And even if Bernie survived those 90% false accusations of treachery, what then? All those billionaires with all that money at their disposal, are they going to willingly let a Social Democrat President break up their businesses? They will fight with every one of their inexhaustible means to keep a Sanders presidency from compromising their business interests. Bernie would be unable to enact any part of his agenda unless Democrats controlled both houses, if anything, he would become the reason for big business to extend its corporate power still much further. And even then, there are so many Democrats in the pocket of special interests that he'd find it no less impossible than Obama ever did.
And even if by some miracle Bernie ever got a mandate for the changes he demands, what then? All those billionaires still have all that money at their disposal, all those congressmen in their pockets, with a military and police force extremely sympathetic to their views. It doesn't take all that much to remove a head of state from office by force if 3/4ths of America's most powerful people give their permission.
Look up Salvador Allende and Augusto Pinochet. That is our worst-case scenario. As far as murderous military dictators go, it can get still a lot worse than Pinochet, he wasn't Hitler, he wasn't even Castro. But he was a dictator, and he was immeasurably terrible compared to anything this country ever experienced. And it's particularly every leftist in the world who considers Pinochet scarcely less terrible than Hitler. Everybody who supported Bernie Sanders from the beginning are the people who could stand to lose the most.