There was one grown-up onstage last night in Detroit, trying to tether his party to reality.  Unless John Delaney's candidacy catches fire, the Democrats will match straight toward the disaster that Rahm Emanuel cautioned them about Monday:

Former Chicago Mayor Rahm Emanuel warned Democratic presidential contenders Monday not to "win the nomination in a way that forecloses a path to victory in the general election."

John Delaney had what many consider the best moment of the debate, telling Bernie Sanders why his Medicare for All program would seriously degrade the quality of health care (via Grabien):

Grabien screen grab.

DELANEY: "So the bill that Senator Sanders drafted by definition will lower quality in health care because it says specifically that the rates will be the same as current Medicare rates, and the data is clear, Medicare does not cover the cost of health care. It covers 80% of the cost of health care in this country, and private insurance covers 120%. So if you start under paying all the health care providers, you're going to create a two tier market where wealthy people buy their health care with cash and the people who are forced like my dad, the union electrician — "

TAPPER: "Thank you, congressman."

DELANEY: "Who will have that health care plan taken away from him — "

TAPPER: "Thank you, congressman."

DELANEY: "They will be forced — "

TAPPER: "I want to give Senator Sanders a chance to respond."

SANDERS: "Under Medicare for all, the hospitals will save substantial sums of money because they won't be spending a fortune doing billing and the other bureaucratic things they have to do today."

DELANEY: "I've done the math — "

SANDERS: "Maybe you did that and made money off of health care but our job is to run a non-profit health care system. Third of all, third of all, when we say $500 billion a year by ending all of the incredible complexities that are driving — "

TAPPER: "Thank you — "

SANDERS: " — every American crazy, trying to deal the health insurance companies —"

TAPPER: "Congressman Delaney. I will let you have a chance to respond."

DELANEY: "His math is wrong. That's all I'm saying. His math is wrong. It's been well documented that if all the bills were paid at Medicare rate, which is specifically — I think it is in section 1200 of their bill in then many hospitals in this country would close. I've been going around rural America and ask rural hospital administrators one question, if all your bills were paid at the Medicare rate last year, what would happen? They all look at me and say we would close. But the question is why do we have to be so extreme? Why can't we just give everyone health care as a right, and allow them to have choices — "

Delaney is an entrepreneur who started two companies now listed on the New York Stock Exchange before running for Congress.  He gave up his seat to run for president.  So far, he has not caught fire, and if he doesn't pick up a substantial bump in support, he won't be on the stage at the next round of debates.

For his trouble, Delaney received a rebuke from Elizabeth Warren, who asked him, why bother to run for president if you're not going to offer fantasy?  (I paraphrase.)

Delaney stubbornly stuck to reality, an electoral appeal that seems to have little appeal to the Democrat base.  Via Grabien:

So I think Democrats win when we run on real solutions, not impossible promises. When we run on things that are workable, not fairy tale Economics, look at the story of Detroit, this amazing city that we're in. This city is turning around because the government and the private sector are working well together. That has to be our model going forward. We need to encourage collaboration between the government, the private sector and the nonprofit sector ...

The Dems can't say they weren't warned.