In this edition: The left wrestles with a possible Sanders-Warren split, state Republican parties keep protecting the president from his challengers, and new polls make the electability fight even more confusing.

I am not a U.K. election expert, but I can pretend to be one on Twitter, and this is The Trailer.

When the Center for Popular Democracy Action endorsed Sen. Bernie Sanders (I-Vt.), it made several arguments at once. First, Sanders had embraced the left-wing coalition’s immigration stance — a moratorium on all deportations — and Democrats needed to follow him. Second, Sanders was in a strong position to beat President Trump if he became his adopted party’s nominee.

The third argument, according to CPDA’s co-president, Ana María Archila, was more of an “intervention" for fellow left-wingers.

“We wanted to propel others to jump in,” she said. “We cannot sit on the sidelines as we watch this primary play out and allow a neoliberal be elected. If we stay divided, the corporate Democrats will pick the nominee.”

That was the left's nightmare scenario, and it was getting more believable at the worst possible time. The year began with a weak-looking Sen. Elizabeth Warren (D-Mass.) posing no threat to Sanders; by summer, Warren had jumped past Sanders and the rest of the field. Now, with Warren's momentum fading, the two Democrats most broadly acceptable to the left have been splitting endorsements and capturing separate swaths of the electorate. 

Centrists who had worried about Warren romping in Iowa and New Hampshire are less nervous now, with South Bend, Ind., Mayor Pete Buttigieg surging in those states and former vice president Joe Biden holding his lead in upcoming Southern primaries.

"The far-left bloc is smaller than the candidates expected," said Jim Kessler, the co-founder of the business-friendly centrist group Third Way, which Sanders feuded with this summer. "They haven't expanded their base. It feels a lot like 2018: The left was ascendant, and then suddenly, when voters came in, they voted for mainstream candidates."

The primary debate has moved further left than Third Way wanted. No leading candidate has embraced the ideas, like a "small-business bill of rights," offered at the centrists' conferences. Buttigieg, who has been attracting most of the left's fury recently, has embraced some of its less economically disruptive ideas, such as banning private prisons and legalizing marijuana while helping victims of the war on drugs. And both Biden and Buttigieg get big applause when they single out Amazon, a target of both Warren and Sanders, to argue for higher, fairer corporate taxes. (Jeff Bezos, the founder of Amazon, owns The Washington Post.)

But the left began this year with its eye on the nomination; the movement's gatekeepers, strengthened during the Trump years, wanted to pick the nominee. That has been getting harder. Groups that grew out of electoral politics, and close combat with the Democratic Party's establishment, have generally sided with Warren, who combined populist politics and good relationships with Democrats. The Working Families Party endorsed her. MoveOn members have preferred her to Sanders in their straw poll, as have readers of the Daily Kos. While the Progressive Change Campaign Committee has endorsed Warren, the similarly aligned Democracy for America has stayed neutral, explaining that its membership is enthusiastic about both candidates.

"A supermajority of our members support both Bernie and Warren," DFA's Charles Chamberlain said. "They're competing against a corporate wing that has all the money and power and can’t get more than 25 percent of voters behind one candidate. Let’s be clear: They have more candidates than us splitting the vote. If I were Third Way, I’d be more concerned with their side than ours."

But Sanders, who runs stronger than Warren with working-class Democratic voters, has pulled more support from groups less focused on Democratic power politics, such as the CPD Action and Democratic Socialists of America. She has won no endorsements, yet, from labor unions; Sanders has won over National Nurses United and several other unions that supported him in 2016.

But many liberal groups are sending a message that either Sanders or Warren would be acceptable, and most members of the Congressional Progressive Caucus are, for now, neutral.

Neither Biden nor Buttigieg has the labor support that Hillary Clinton did, which could have provided openings to a left-wing candidate in 2020. The presence of two left-wing candidates has stopped them from taking advantage. In The Washington Post's average of national primary polls, Sanders's and Warren's support is a combined 34 percent; support for Sanders at this point in the last primary was at 31 percent.

Asked whether the left needs to consolidate, activists tended to argue that there was plenty of time to deal with that. "We're with Warren, but we think Warren and Sanders are giants of the progressive movement," said WFP spokesman Joe Dinkin. 

The first few primaries could decide the left's next move, with pressure on Warren or Sanders to quit if either begins losing. There is no evidence of consolidation until then, as Sanders struggles to match his support from the spring and Warren struggles to recover her strength from the summer. 

For the PCCC, which immediately endorsed Warren but praised Sanders when he joined the race, the play is obvious: Convince nervous Democrats that either Warren or Sanders could win the general election.

"There are a lot of scared progressives who I call 'electability voters,' " said Adam Green of the PCCC. "They've been parked with Biden, and lately they've been parked with Pete. Elizabeth Warren's rise didn't come from cannibalizing Bernie; it came from those electability voters. For anyone who's worried about this, the most important thing they could do is communicate to members that the transformational message of Warren and Sanders can win."

In the past few days, Warren and Sanders have made sharper contrasts with Biden and Buttigieg, though not by name. During his latest swing through Nevada, Sanders singled out candidates who were not, like he or Warren, avoiding high-dollar fundraisers.

"One of my Democratic opponents has taken donations from, I think, 44 billionaires,” Sanders said Monday. “Another candidate is busy running around the country going to wealthy peoples' homes, asking them for money."

On Thursday, Warren delivered a set-piece speech in New Hampshire, largely restating her anti-corruption campaign themes but leaving a few bear traps for Biden and Buttigieg.

“We know that one Democratic candidate walked into a room of wealthy donors this year to promise that ‘nothing would fundamentally change’ if he’s president,” said Warren, in a reference to Biden. “We know that another calls the people who raise a quarter-million dollars for him his ‘National Investors Circle,’ and he offers them regular phone calls and special access. When a candidate brags about how beholden he feels to a group of wealthy investors, our democracy is in serious trouble.”

Campaign finance transparency had not become the defining issue that either candidate hoped; Biden had reneged on his pledge never to endorse a super PAC, to no apparent voter backlash. But after a long month of infighting, with Medicare-for-all advocates attacking Warren’s revisions to her health-care plan, the party’s left is focused on attacking Buttigieg and Biden. Any further unity will have to wait.

“There’s every possibility that Bernie and Warren are the top two finishers in Iowa,” Chamberlain said. “That could happen. If it did, it wouldn’t matter if they are splitting votes. It would be, let the best person win.”

This newsletter originally misquoted Adam Green on Warren and Sanders; the quote has been corrected.

READING LIST

“Biden clearly doesn’t like talking about his son’s overseas business dealings. Lately, it’s been an unavoidable topic on the campaign trail,” by Cleve R. Wootson Jr.

The Hunter question, and the search to find a good answer for it.

“Bernie Sanders is sitting out one of the most exciting House primary races,” by Daniel Marans

Why the leader of the political revolution is absent from the fight against a conservative Democrat.

“As Democrats trade barbs on business ties, some worry purity tests are going too far,” by Sean Sullivan and Matt Viser

Some Democrats are getting tired of the name-your-donors game.

“Can you spot the fake? Hint: Look at the pundits,” by Rebecca Traister

Why every candidate dissembles but only some get accused of being untrustworthy.

“Trump health promises thwarted by feuding aides, shifting orders,” by Yasmeen Abutaleb, Josh Dawsey, Paige Winfield Cunningham and Amy Goldstein

Policy jitters that could have a big 2020 impact.

“National Democratic groups litigate 2020 in the courts,” by Simone Pathé

Inside the long-term war against (and for) gerrymandering.

WHAT I'M WATCHING

I am Warren, hear me roar. In the week since Sen. Kamala D. Harris of California ended her presidential campaign, Sen. Elizabeth Warren (D-Mass.) has spoken more pointedly about something not always helpful to her own campaign: gender. At events over the past few days, and in donor appeals, Warren invoked Harris and Sen. Kirsten Gillibrand (D-N.Y.) to warn Democrats that qualified women were being knocked offstage.

“Kamala Harris and Kirsten Gillibrand — two women senators who, together, won more than 11.5 million votes in their last elections — have been forced out of this race, while billionaires Tom Steyer and Mike Bloomberg have been allowed to buy their way in,” one email to donors read.

On Tuesday night, the president himself seemed to help Warren, making two dismissively gendered attacks on her. In a reference to an 11-month-old video of Warren drinking a beer while her husband Bruce Mann stayed off-screen, Trump joked that she probably hadn't “seen him in 10 years.” In a short summary of Warren's campaign, Trump said that “she rose, she rose, and she became strong, but then she opened that fresh mouth of hers and it stopped.”

It was both an insult and exactly the stuff that Warren had benefited from during her rise. (“Nevertheless, she persisted” T-shirts pop up in Iowa even outside Warren's rallies.) Asked on Thursday if she felt “men were always telling her to sit down,” Warren let out an excited “yes!” 

Warren is not the only woman left in the race; Sen. Amy Klobuchar (D-Minn.) is popular in Iowa, and Rep. Tulsi Gabbard of Hawaii is not going anywhere. But Warrenworld sees an advantage if, at some point, Democratic voters think that every female candidate could be pushed out of the race. Democrats started both of their last primaries, in 2008 and 2016, taking for granted that Hillary Clinton was in the strongest position. This year, Warren has been the only female candidate to lead in polls, briefly, in September and October.

IMPEACHMENT WATCH

The latest on the impeachment process: 

AD WATCH

Andrew Yang, “Wait.” The math-centric candidate's campaign has become a lot more ordinary recently, as it has added staff and risen in polls. Here, Yang tackles an issue at the center of the primary, climate change, and sounds like other candidates (“end the corporate handouts”) until the very end: He supports a “constitutional climate amendment to protect our future.”

American Action Network, “Pay Price.” The anti-impeachment ad campaign against House Democrats has been fairly inexpensive. AAN has spent around $10 million, less than one-third of what Mike Bloomberg spent on the first week of his campaign. But it's consistent, using impeachment as a club to argue that swing-district Democrats refuse to get real work done. “No progress on health care, securing the border, or job-creating trade deals,” a narrator sighs. The ad went up exactly 24 hours before House Democrats embraced their negotiated version of the USMCA trade deal, the labor-backed revision of NAFTA, something the vulnerable Democrats wanted to make the case that they are not entirely focused on impeachment.

POLL WATCH

California Democratic primary (CNN-SSRS, 1203 voters)

Joe Biden: 21% 
Bernie Sanders: 20% 
Elizabeth Warren: 17% 
Pete Buttigieg: 9% 
Andrew Yang: 6% 
Mike Bloomberg: 5% 
Cory Booker: 3% 
Tulsi Gabbard: 2% 
Amy Klobuchar: 2% 
Julián Castro: 1% 
Tom Steyer: 1%

CNN's first look at California is in line with recent state polling: a jumble at the top, with some decline from Elizabeth Warren's summer numbers mostly benefiting lesser-known candidates. Warren has a base: white voters with college degrees. She benefits from a gender gap, too, winning 20 percent of women but just 12 percent of men. The starkest gap for her rivals is age: Sanders leads the field by 12 points among voters under 50, while Biden leads by 23 points among voters over 65. 

A race this close wouldn't benefit any of the top three candidates in particular; if three candidates crack 15 percent, they'll each grab from a gigantic delegate pool, with candidates in safe Democratic seats (with more delegates) faring best. One reason for the closeness is that Californians, who have voted reliably blue for president since 1992, don't see Biden as far and away their most electable choice: Just 23 percent of voters say he's the strongest choice against Trump, to 17 percent for Sanders and 16 percent for Warren.

Texas Democratic primary (CNN-SSRS, 1205 voters)

Joe Biden: 35% 
Bernie Sanders: 15% 
Elizabeth Warren: 13% 
Pete Buttigieg: 9% 
Mike Bloomberg: 5% 
Julián Castro: 3% 
Andrew Yang: 3% 
Cory Booker: 2% 
Tom Steyer: 2% 
Michael F. Bennet: 1% 
Tulsi Gabbard: 1% 
Amy Klobuchar: 1% 
Deval Patrick: 1%

Bernie Sanders's post-Iowa plans rely in large part on his popularity with Latino voters; he won them in Nevada and California last time. But he has never had the same appeal in Texas, as seen here. Latinos make up more of the Democratic vote in Texas than they do in California, and in 2016 they backed Hillary Clinton by 42 points. Here, nonwhite voters break heavily to Biden, making up most of his lead. As Biden has struggled in early states, his campaign has frequently pointed to the failure of other Democrats to break through with nonwhite voters. California could obscure the size of that advantage, unless there is a break away from Biden after the first voting.

2020 election in Wisconsin (Marquette Law, 800 registered voters)

Joe Biden: 47% ( 3)
Donald Trump: 46% (-1)

Donald Trump: 47% ( 0)
Bernie Sanders: 45% ( 1)

Donald Trump: 45% (-3)
Elizabeth Warren: 44% ( 1)

Donald Trump: 44% (-3)
Pete Buttigieg: 43% ( 4)

Donald Trump: 44% ( 0)
Cory Booker: 43% (-2)

Some polls matter more than others. The last edition of Wisconsin's benchmark poll was one of them: It found every Democratic hopeful trailing Trump in a key state, some of them trailing outside the margin of error. That sparked a Democratic panic even more intense than their usual, slow-burning panic, and it mattered, as Mike Bloomberg would jump into the race a few weeks later saying that his own data also showed that the Democratic hopefuls were trailing Trump in the Midwest. 

There's not as much panic fuel here: Democrats see a close race with a president who, at his strongest level of support, isn't matching his 2016 numbers. (Trump won the state thanks to a surge among the last undecided voters and nearly 6 percent of voters going third party.)

DEBATE SEASON

Despite near-daily criticism about its debate rules and which candidates they're excluding, the Democratic National Committee has stuck to the plan it set out at the start of the year: Six debates in 2019 and six more in 2020, starting in early primary states. 

On Thursday, the party announced the dates, locations and sponsors of the next four debates, which will be held in the weeks around the first primaries and caucuses.

Jan. 14. Des Moines, at Drake University. Media partners: CNN and the Des Moines Register. (Those same media outlets collaborate on the industry standard Iowa Poll.) 

Feb. 7. Manchester, N.H., at St. Anselm College. Media partners: ABC, WMUR-TV and Apple News.

Feb. 19. Las Vegas, no announced stage site yet. Media partners: NBC News, MSNBC, and the Nevada Independent. 

Feb. 25. Charleston, S.C., at the Gaillard Center. Media partners: CBS News, the Congressional Black Caucus Institute, and Twitter.

Scheduling just one debate in the 30 days before voting starts is significant and slightly unusual. In January 2016, Republicans held two debates while Democrats held just one, but the party's skimpy debate schedule angered activists. (The party would later add two debates to its schedule, in Michigan and New York.) In 2008, when the caucuses were held in January, two Democratic debates were held in December.

This year is different in one important way: Five of the candidates for president, three of whom are qualifying for every debate, serve in the U.S. Senate. And unless something knocks House Democrats off course, senators now expect to spend part of January sitting for an impeachment trial six days a week. 

That will add logistical difficulties to the January debate, which takes place on a Tuesday. If the trial ends at 5 p.m. that day and Democrats caught or chartered a direct flight to Des Moines, they would probably land just an hour before the start of the debate. (The flight takes two hours, and debates have tended to begin at 9 p.m.) The DNC could have prevented this with a debate in Washington but the rules forbade that; the party agreed to host debates in early-voting states at the start of 2020.

2020

The Dec. 19 debate stage will almost certainly stick at seven candidates: former vice president Joe Biden; Sen. Elizabeth Warren (D-Mass.); Sen. Bernie Sanders (I-Vt.); South Bend, Ind., Mayor Pete Buttigieg; Sen. Amy Klobuchar (D-Minn.); and businessman Tom Steyer. There are six hours left, on the East Coast, for four polls to qualify Julián Castro or Cory Booker. But neither campaign expects to make it, as Booker's campaign manager, Addisu Demissie, told reporters Thursday morning.

“There have only been four polls since the last week of this campaign, when we all know that we've seen a surge of momentum,” Demissie said, referring to the period after Sen. Kamala D. Harris quit the race. “We're a campaign that does not have $100 million to spend on campaign advertising. Counting on national polls was never what we intended to do and was always going to be a tall order.”

Booker's campaign, instead, imagines a “path to victory that does not run through the December debate stage.” It starts in Iowa, where the campaign must do “better than expected;” continues through New Hampshire, where it could muddle through; and gets wider if the campaign can start “proving our viability in diverse communities in Nevada, then South Carolina.”

Castro, who has reframed his own campaign around criticism of the first two primaries and their whiteness, came to Des Moines on Tuesday for a dedicated town hall about it. Talking like that, Castro said, probably hurt his future ambitions but would be worth it for the party. 

“I don’t think it serves anybody to stay quiet about the structure of our elections,” Castro said, then tied it to the hotly contested Georgia gubernatorial election of 2018, with allegations of vote suppression. “If we say, 'Well, we don't really have to do anything about the Iowa caucus,' well, then, do we have to do anything about that secretary of state in Georgia?” 

Joe Biden. He concluded a three-candidate town hall series with Nevada's culinary workers, which made him the only candidate they heard from who opposed Medicare-for-all. While Elizabeth Warren escaped unscathed and Bernie Sanders was heckled, Biden got applause for saying he would never touch union health-care plans. He also added Rob Flahery, the digital director for Beto O'Rourke's campaign, to his online team. 

Pete Buttigieg. He sat for a “CBS This Morning” interview during his New York swing, making more veiled criticisms of his rivals than he did during his first open-to-the-media fundraiser. Among those criticisms: Buttigieg called himself the only candidate on the debate stage who's not a millionaire, which is true and which weaves around the personal stories that Warren, Biden and Sanders (who grew up poorer) make on the trail. And Buttigieg scored the endorsement of Iowa State Sen. Bill Dotzler.

Deval Patrick. He's crying foul about Michigan ballot standards, which force him to turn in more than 10,000 signatures for ballot access because he didn't tell the state party he was running until a previous deadline passed.

Amy Klobuchar. She delivered a foreign policy address in Washington that restated much of what she says on the trail: The president has made the country less safe by breaking strong alliances. She also added a labor roundtable to her swing through Florida, meeting with workers in Miami.

Andrew Yang. He parted with a campaign staffer over an unspecified sexual misconduct allegation, the first real blast of negative coverage for his campaign.

John Delaney. He's returning to Iowa this weekend for events with Clinton and Muscatine Democrats; his campaign points out that no other Democrat will attend them, as they hold their own rallies. 

Bernie Sanders. He endorsed Cenk Uygur, the host of the Young Turks news network, who is running for Congress in California’s 25th District. Many leading California Democrats, including House Speaker Nancy Pelosi (D-Calif.) and Gov. Gavin Newsom, have endorsed Assemblywoman Christy Smith.

Mike Bloomberg. He released a letter from his physician pronouncing the 77-year-old candidate to be in “outstanding health.”

ON THE TRAIL

Primary challenge? What Trump primary challenge? While Republicans in Congress close ranks around the president, the party in the states is going even further, canceling contests with plans to award all delegates to the Trump campaign.

On Wednesday, Hawaii Republicans announced that the state's 19 delegates would be bound to Trump, a full five months before the state holds its primary. Hawaii had previously held a caucus, which Trump in 2016 won by just 11 points.

“Hawaii Republicans across the state are united in their support of President Trump,” state party chair Shirlene Ostrov said in a statement.

The same day, a South Carolina court tossed out a lawsuit filed by Republican critics of the president in South Carolina, where the state party voted to cancel the primary altogether — even as former governor Mark Sanford was seeking the presidential nomination. (Sanford quit his campaign last month.) 

“The law does not give Plaintiffs a legal right to a presidential preference primary, and the Court will not substitute its own judgment for that of the General Assembly or the SCGOP,” Judge Jocelyn Newman wrote.

Republican efforts to protect Trump from a primary have stepped up even as the president's challengers, former Massachusetts governor William Weld and former Illinois congressman Joe Walsh, have struggled for traction. Republicans in Minnesota, where parties determine who appears on their ballot, submitted only Trump's name.

“It's a token of the president's desire to avoid any sort of competition or open dialogue whatsoever,” said Weld in an interview, during a Thursday visit to D.C. “The situation I regret the most is in Alaska, because it's a libertarian-leaning state, and because I have a friendly relationship with Sen. Lisa Murkowski. She won in 2010 as a write-in candidate, so we're looking at that option.”

COUNTDOWN

... two days until runoff elections in Houston
... seven days until the sixth Democratic debate
... 53 days until the Iowa caucuses
... 61 days until the New Hampshire primary
... 72 days until the Nevada caucuses