On Wednesday in Washington, Sen. Bernie Sanders debuted a very big, wildly ambitious piece of legislation. Dozens of approving activists, plus a handful of its impressive legion of Senate cosponsors, almost all of them potential presidential candidates, turned out for the unveiling.

But the scene wasn't the thing. The bill was. Sanders' "Medicare for all Act of 2017," the latest edition of his single-payer health care plan, outshone all the political star power in the room -- the headlining Vermont senator included.

When a party is so roundly beaten as the Democrats, leveled at all levels of government, there is an inclination to fixate on certain characters in their tragedy. Or comedy. The Democrats in 2017 never seem to stray too far from either. So it was rare, if only for a few hours, to see the politicians recede into the politics.

A different kind of politics.

Sanders' plan is, by any standard and his own admission, an incomplete one. Frustratingly so, to many. There's little institutional backing and no clear price tag. We know there will be tax hikes, though not too much more about the finances . Instead, the focus is on rallying support for the idea. Sanders will do some barnstorming now, soliciting tweaks, edits and ideas from around the country.

Mostly, though, he will try to convince people. To create opportunity where the data says there is none.

This is not an easy thing to do. Democrats during the past eight or so years mostly stopped trying. Former President Barack Obama ran two fairly progressive, populist-tinged campaigns. But he was governed, in office, by pragmatism. When Hillary Clinton's turn came, for the second time, she seemed paralyzed by it. In her new book, Clinton writes that she spent weeks studying and weighing whether to propose a universal basic income (UBI) program. It never happened.

"Unfortunately, we couldn't make the numbers work," she explains, adding a few lines later: "I wonder now whether we should have thrown caution to the wind and embraced (the idea) as a long-term goal and figured out the details later."

The anecdote provides a neat summary of where a certain sort of political pragmatism leads. That's not to say Clinton made the wrong decision. UBI is a complicated policy, laden with all kinds of ideological tripwires. If your argument for it relies too heavily on "Hey, the numbers work," then it's probably better to stand down. But Clinton did understand the underlying appeal. (At least in the way many on the left would frame it.)

"Besides cash in people's pockets," she writes, it "would also be a way of making every American feel more connected to our country and to one another -- part of something bigger than ourselves."

Economic empowerment stripped of the resentment -- or stigma -- that comes with means testing. By definition, universality. Still, she demurred. This is instructive on a few levels.

Clinton's rejection of an ambitious policy that clearly resonated with her personally because of "the numbers" is almost too on the nose, like a lazy Saturday Night Live sketch. But it's not unique to her. The same logic is pervasive in the writings of many of single-payer's most strident liberal critics . In most cases, it's not the hoped-for outcome they oppose, but the process.

In this construction, policy must come first, then the support of "smart" politicians, whose job it is to sell the package to the voting public. To reverse engineer that, allowing the movement to shape the policy -- and choose the priorities -- is an apostasy.

Never mind for a minute the merits of single payer or whether Sanders' version will, one day, become law. It could happen. Or not. I wouldn't recommend wagering anything, in either direction, you couldn't afford to lose. Anyway, it hardly matters. That's the end of the conversation.

This is the beginning. This is the news: Democrats -- senators, activists, supporters, staffers -- are actually telling people what they want to do. And it's something they will have a very hard time achieving.

That is not how the party and its supporting institutions normally operate. As CNN's Eric Bradner wrote on Wednesday , "The left spent more than a decade developing a consensus around the policies that went into former President Obama's Affordable Care Act. But liberal think tanks and research groups are just starting that work on single-payer health care."

It's not that the the policy wonks have laid down their pens. The Sanders team spent months on this bill. New York Sen. Kirsten Gillibrand on Wednesday touted the hand she and hers had taken in writing one of its more innovative and detailed elements. Massachusetts Sen. Elizabeth Warren cast the current effort as the next chapter in a project that dates back to Franklin Roosevelt. California Sen. Kamala Harris touted the fiscal upside.