A big reason you’re not seeing a coalition around Sanders is because every policy and reform he puts forth he doesn’t have a price tag on it. Anyone that is halfway fiscally minded is not going to be rushing to the ballot box to vote Bernie. I know he keeps mentioning “cancelling” student debt but at the end of the day someone has to pay for that and that will be the tax payers. So anyone who doesn’t want to see taxes go up that’s another strike for them on Bernie.
The vast vast vast majority of tax payers won't be affected by that pledge. From his website: https://berniesanders.com/issues/free-college-cancel-debt/
"We can guarantee higher education as a right for all and cancel all student debt for an estimated $2.2 trillion. To pay for this, we will impose a tax of a fraction of a percent on Wall Street speculators who nearly destroyed the economy a decade ago. This Wall Street speculation tax will raise $2.4 trillion over the next ten years. It works by placing a 0.5 percent tax on stock trades – 50 cents on every $100 of stock – a 0.1 percent fee on bond trades, and a 0.005 percent fee on derivative trades.
If Wall Street can be bailed out for several trillion dollars, 45 million Americans can and will be bailed out of the $1.6 trillion burden of student loan debt and we can provide free college for all."
And on his radical suggestions, it wouldn't be totally unprecedented for people to assume that hardly anything democrats put forth will be approved when going against republicans in the senate and house. This is wishful thinking, but they might as well start lofty. My point is, a leftist candidate is the best choice for the democratic party to win. It always has been. And the sooner the people start seeing through corporate lies that protect the ultra wealthy, the more momentum he's gonna get. The questions is, if the true goal is to win, how smart are the democrats and their voters? This is an identity challenging race. You may find out soon enough if they'd rather have 4 more years of trump, than a sanders presidency at all. Pay attention to the media and how they'll spin this, despite bernie winning, as an underachievment, and talk more about amy/pete. If another candidate had Bernie's success: winning the popular vote in both states, raising more than 25 million in January alone, leading the non white vote, highest voter turn out among young adults, they would be all in.