Nearly 18 hours of Democratic debating – six sessions, from June to December – have clarified or clouded the crystal ball. We know exactly how this race is going to go, or we have absolutely no clue whatsoever.

Joe Biden topped the pack all year long, despite various mini-stumbles and lots of ridicule on lefty Twitter (which most people don’t use), and there’s no reason to think he can’t sustain his lead through the ’20 primary season. In that sense, the race has been remarkably stable and is likely to remain so – unless someone topples him by somehow unifying a party that is racially, generationally, and ideologically divided.

Biden is strong with black people (especially older blacks) and blue-collar whites, but weak with young people and college-educated white liberals. Bernie Sanders is strong with young people and Latinos, but weak with older folks (the most reliable voters). Elizabeth Warren is strong with college-educated white liberals, but weak with black people and the non-college educated. Pete Buttigieg is strong with college-educated white liberals (especially in Iowa, the starting-gate state), but invisible elsewhere with black people. Amy Klobuchar, Pete’s fellow mid-westerner, wants to supplant him in Iowa, which explains her ferocity toward him during the final debate of 2019 (we’ll get to that).

These fractures are reflected in the latest national polls. NPR/PBS/Marist says Biden has 24 percent of all Democrats, with Sanders at 22, Warren at 17, and Buttigieg at 13. IBD/TPP has Biden at 26, Sanders at 18, Warren at 14, and Buttigieg at 9. Monmouth has Biden at 26, Sanders at 21, Warren at 17, and Buttigieg at 8. Quinnipiac has Biden at 29, Sanders at 17, Warren at 15, and Buttigieg at 9. All of which suggests that the race is very stable – until you notice this NPR/PBS/Marist stat: 76 percent of Democrats said they could still change their minds.

In last night’s debate, Biden did nothing to dislodge himself. When asked whether he could work with Republicans after defeating Trump, his answer was solid (at minimum, his steadfast Democratic followers will perceive it as solid):

“With Trump out of the way…he’s not going to be able to intimidate the base, his base is not going to be able to intimidate those half a dozen (congressional) Republicans we may need in other things. I refuse to accept the notion, as some on this stage do, that we can never, never get to a place where we have cooperation again. If that’s the case, we’re dead as a country. We need to be able to reach a consensus.

“And if anyone has reason to be angry with the Republicans and not want to cooperate, it’s me – the way they’ve attacked me, my son, and my family. I have no love. But the fact is, we have to be able to get things done. And when we can’t convince them, we go out and beat them like we did in the 2018 election in red states and in purple states.”

If Biden were to win Iowa – one national poll says he’s narrowly on top – he’d likely have sufficient momentum to survive losses in New Hampshire and Nevada (which votes third), recoup in South Carolina (where black voters drive Democratic turnout), and roll up wins on 11-state, delegate-rich Super Tuesday (assuming he can neutralize billionaire Michael Bloomberg’s advertising blitz). But none of that may happen. Or Biden could lose Iowa and still win the nomination, which has happened before (Bill Clinton, 1992). Indeed, Pete Buttigieg is currently the flavor of the month in Iowa, topping two state polls, and even though an Iowa win guarantees nothing (just ask President Dick Gephardt, the Iowa winner in 1988), it’s often do-or-die for underlings who are desperate for traction.

In other words, Warren and Klobuchar. Warren has lost ground in recent weeks, since taking (and partially walking back) the suicidal position that all Americans should be forced into government health care, losing their private coverage in the process. Klobuchar has been consistently polling around four percent. To survive, she needs a strong showing in Iowa, and Mayor Pete is in her way. Warren needs a comeback, which requires a strong showing among Iowa’s college-educated whites – and Mayor Pete is in her way.

Which explains why the vibe got nasty last night. Warren said she didn’t like the way Buttigieg recently raised money in California’s Napa Valley:

“The mayor just recently had a fundraiser that was held in a wine cave full of crystals and served $900-a-bottle wine…Billionaires in wine caves should not pick the next president of the United States!”

Buttigieg, clearly anticipating her attack, lashed back:

“According to Forbes magazine, I am literally the only person on this stage who is not a millionaire or a billionaire…This is the problem with issuing purity tests you cannot yourself pass. If I never to be in the company of a progressive Democratic donor, I couldn’t be up here. Senator, your net worth is 100 times mine…The maximum (donation) allowable by law (is) $2,800, would that pollute my campaign because it came from a wealthy person? No, I would be glad to have that support.”

Warren, in high dudgeon:

“I do not sell access to my time. I don’t do call time with millionaires and billionaires. I don’t meet behind closed doors with big dollar donors.”

Buttigieg, twisting the knife:

“Senator, your presidential campaign right now as we speak is funded in part by money you transferred (from her Senate campaign kitty), having raised it at those exact same big-ticket fundraisers you now denounce. Did it corrupt you, Senator? Of course not. So to denounce the same kind of fundraising guidelines that President Obama went by, that Speaker Pelosi goes by, that you yourself went by until not long ago, in order to build the Democratic party…these purity tests shrink the stakes of this most important election.” (Warren had no answer to that.)

At a time when an impeached, unprecedentedly corrupt president sits in the White House, all this squabbling about who has the most morally pure donations seemed ridiculous, but hey, these are Democrats.

Klobuchar targeted Buttigieg from a different direction. Basically, her message was: He and I are both practical progressives from flyover country, but I’ve got the governing chops and he’s wet behind the ears.

After he made a passing disdainful remark about the workings for Congress, she picked a fight:

“While you can dismiss committee hearings, I think this experience works. And I have not denigrated your experience as a local official…I just think you should respect our experience.”

To which Buttigieg basically said, Oh yeah? I was in the military, try to top that:

“I raised my right hand and swore to defend (the Constitution) with my life. That is my experience. And it may not be the same as yours, but it counts, Senator. It counts.”

To which Klobuchar basically said, Oh yeah? If we’re talking about experience, I’m a winner and you’re a loser:

“I certainly respect your military experience. That’s not what this is about. This is about choosing a president…I know you ran to be chair of the Democratic National Committee (and lost, in 2017). That’s not something that I wanted to do. I want to be president of the United States. And the point is, we should have someone heading up this ticket that has actually won…I have done it (as a Senate candidate) three times.”

To which Buttigieg said, Oh yeah? Check out my vote share:

“If you want to talk about the capacity to win, try putting together a coalition to bring you back to (mayoral) office with 80 percent of the vote as a gay dude in Mike Pence’s Indiana.”

To which Klobuchar said, Oh yeah? You’re still a loser, you were trounced nine years ago in your race for state treasurer:

“If you had won (statewide) in Indiana, that would be one thing. You tried and you lost by 20 points. I’m sorry. That’s just the math.” (Actually, he lost by 25 points.)

Hey, that’s politics. Buttigieg is on top in Iowa (possibly in New Hampshire as well), so he gets targeted. When Warren was surging a few months ago, she was targeted. Biden, leading all year, has been repeatedly targeted. Will any of them, or anyone else, survive this scrum and primary gauntlet with the requisite coalition strength to save us from Trump?

Who knows. It makes me want to drink myself silly in a wine cave.