In this edition: The myths of the pollercoaster, a talk with (another one of) the president’s potential primary challengers, and the last congressional debate of the year.

If I am not currently trending on Twitter, assume that it’s because of a dastardly blackout.

The Labor Day holiday weekend is always a curious one for campaigns — some are going dark, and some are going everywhere. If you have a question about anything happening in the primary, email david.weigel@washpost.com with “Trailer” in the subject line and look for the answer Sunday.

The Democratic presidential field is getting easier to sort into categories. There are the 10 candidates who made the September debate and the 10 candidates who didn’t. There are the candidates who want to talk about poll numbers and the candidates who say that polling in a Democratic primary has often led the media astray. 

“Gosh, I don’t want to be leading in the polls right now,” Sen. Cory Booker of New Jersey told reporters this month at the Iowa State Fair. “The polls in all the past elections of my lifetime have never been predictive.” 

Sen. Michael F. Bennet of Colorado had a similar message for reporters last weekend, at the Democratic National Committee meeting in San Francisco: “Barack Obama was 30 points behind Hillary Clinton in November of the year before.”

Is this true? Is there still time for a breakout? Have candidates leading at this point gone on to fumble the nomination away? Now that Democratic primary polling is pushing candidates out of the race — and after a week when one outlier Monmouth poll generated tons of coverage — it's worth looking at what the mess of polling has been able to tell us and what it’s gotten wrong, based on every primary race since 1999.

Some campaigns are stretching for examples of how they could still surge; some analysis of where voters are moving ignores how they’ve moved in the past. To tackle just three widely shared beliefs:

Whoever’s leading in the polls by Labor Day will be the nominee. This is a popular take for people who would like to ignore the daily campaign drama and focus on 2020, but it’s not quite true.

Between the two main parties, there have been eight competitive primaries since 2000: Republicans in 2000, 2008, 2012 and 2016 and Democrats in 2000, 2004, 2008 and 2016. And in 2008, both the Democratic and Republican candidates leading national polls on Labor Day — Rudolph W. Giuliani and Hillary Clinton — went on to lose their party’s nominations.

The 2008 example is the go-to for this year’s Democratic candidates, many of whom imagine themselves breaking out when “voters tune in.” From August through November of 2007, Hillary Clinton led Barack Obama by double digits in every national public poll; Bennet was right when he referred to a poll that had Obama down by 30 points. (The USA Today/Gallup poll in August 2007 had him down by 28.)

The crowdedness of the 2020 field makes it harder to draw comparisons to any other cycle. But there’s no polling “rule” that suggests the race is over. On Labor Day 2011, Mitt Romney was at 27.8 percent support in the national polling average. On Labor Day 2015, Donald Trump was at the exact same level: 27.8 percent. Joe Biden is heading into the holiday at 28.9 percent, around the same level as those two Republican front-runners. “I notice you didn't ask me how I feel about the new CNN poll,” Biden told reporters in Iowa last week, referring to one of the surveys that had showed him ticking up. But still, that’s lower than Hillary Clinton's support on Labor Day 2007 (37.4 percent) or Labor Day 2015 (49.3 percent). His strength, in other words, is comparable to two Republicans who faced long primaries and lower than the last Democratic poll leader, who lost and then won tight two-way races.

If you’re at single digits now, you’re not going to win. The patron saint of last-minute surges is Rick Santorum, whose 2012 campaign, with its call for Republicans to embrace white voters without college degrees, had a longer legacy than most people could have guessed. 

In the summer before the Iowa caucuses, Santorum was basically irrelevant, polling in the low single digits nationally and not much better in Iowa. By the time the caucuses began, Santorum had raised less than $2.5 million; he would go on to wage a three-month primary battle against Mitt Romney, who by early 2012 had raised close to $60 million. While an election-night issue in Iowa cost Santorum a clean win, he did take the state’s caucuses; a better-funded candidate might have broken out and won the whole thing.

No Democrat has pulled off a similar surge. While some, like Booker, point to John F. Kerry’s collapse in the summer of 2003 as evidence that a single-digit candidate can come back, Kerry was always relatively strong in Iowa. By this point in that cycle, he was tied with Howard Dean in the state; when he did fall, it was never lower than third place in a nine-candidate field. Any Democrat who breaks from the low single digits to win the first caucus state will be the first Democrat who ever pulled that off.

Biden (or Sanders) have firewalls with nonwhite voters. Both of these story lines have grown more popular as Sen. Elizabeth Warren of Massachusetts has climbed into the midteens in polls; defenders of both Biden and Sen. Bernie Sanders (I-Vt.) have suggested that she will hit a wall, as soon as the college-educated white voters run out. Support for Biden’s campaign is highest with black voters and older white voters. Support for the Sanders campaign now, as in 2015, skews younger and less wealthy; in the 2016 Iowa caucuses, Sanders won 84 percent of voters under 30 and 53 percent of voters who made less than $50,000 per year. 

The idea that Sanders relies on young, white voters to be competitive has been so toxic, and so irritating to Sanders allies, that they’ve highlighted the polls that contradict it. In April, the Intercept cited the cross tabs of a Morning Consult poll (which is not counted for DNC debates) to argue that Sanders was “the most popular candidate among Hispanic voters”; the numbers put him at 33 percent among those voters. This week, civil rights activist and Sanders supporter Shaun King pointed to the cross tabs of Monmouth’s poll to argue that he had “the most diverse support ethnically” — 22 percent among nonwhite voters, to 19 percent for Biden.

Support for Democrats among nonwhite voters is actually scrambled between several candidates, with an advantage for Biden that’s lower than the one Hillary Clinton had four years ago. At this point in 2015, her support among black voters hovered close to 75 percent; as late as October 2007, Clinton was winning a majority of the black vote, with a lead of 20 points or better over Barack Obama.

This week’s Quinnipiac poll found Biden at 46 percent with black voters, to 10 percent each for Sanders and Warren. National pollsters have rarely broken out numbers on Hispanic voters, but in Nevada, the only early state with a substantial Latino vote, a June poll found Biden with 27 percent, Sanders with 19 percent and Warren with 11 percent.

What does all of this mean? First, the many candidates who think that Biden’s lead can be overcome are not delusional. Second, the candidates still struggling in the early states right now are not likely to do the overcoming. And third, Biden has a bigger advantage with nonwhite voters than other campaigns like to admit — but not as big as the one Barack Obama leaped over in 2008.

READING LIST

“Trump’s revival of claim of voting fraud in New Hampshire alarms some state Republicans,” by Amy Gardner

A local GOP that’s used to false accusations of dirty tricks is now responding to the country’s biggest microphone.

“Democrats disavow Obama’s creation of rival political group,” by Laura Barrón-López, Alex Thompson and Holly Otterbein

The 2020 Democrats have pledged not to keep their own campaign organizations active if they win.

“Can this PAC find more LGBTQ and minority candidates to run as Republicans?” by Rachel Kurzius

The sometimes rewarding hunt for diverse GOP candidates in the Trump era.

“Can Democrats running for president save a journalism industry in crisis?” by Tara Golshan and Ella Nilsen

A new campaign plank for 2020: rescuing local news.

“As he campaigns for president, Joe Biden tells a moving but false war story,” by Matt Viser and Greg Jaffe

How a tale spun out of control.

“Joe Walsh Is Running for 'Morning Joe,” by Alex Pareene

A skeptical look at an anti-Trump candidacy.

“Senate Democrats’ campaign arm is pressuring consultants not to work with leading progressive candidate in Colorado,” by Aida Chávez and Akela Lacy

In 2018, national Democrats intervened in a key Colorado House primary, and not much has changed since.

ON THE TRAIL

Mark Sanford, who will decide “soon” on whether to trade forced political retirement for a long-shot presidential bid, spent Wednesday in Iowa, heading from meeting to meeting.

“I just got through with a dinner at a barbecue place with a guy who has been involved in races around the state,” Sanford said in a phone call. “Before that, I caught up with a guy who’d done the same kind of thing. I’ve just talked to people who have been in the know, to get their take on the appetite for such a challenge.”

Sanford’s “listening tour,” which took him to New Hampshire earlier in the month, is doing two things for his potential campaign. First, it’s teaching him just what it would take to run a hopeless-seeming primary challenge against a president who has put away most critics in his party. (Sanford narrowly lost a primary challenge in 2018 to a Republican critical of his take on Trump.) Second, it’s emphasizing just how much Sanford, who prides himself on his frugality and bluntness, had ruled out another run for office until Trump yanked him back.

“A lot of this has just been at the operative level,” he said. “You know, ‘Tell me how this works. Explain how the caucus process works.’ You know, you talk to certain operatives in the northeast and they say just avoid Iowa altogether. John McCain did that, and he won the nomination. But other people say, ‘No, come and compete here,’ and I was surprised to find that there’s a very high number of independents in this state.”

Sanford’s approach has differed from that of Joe Walsh, the one-term Illinois congressman who jumped into the race this week. Walsh, who spent most of his eight-year political exile as a political commentator, jumped in with a series of TV interviews. Sanford simply put out word that he wanted to figure out how a presidential run would work and started his research.

“The degree to which farmers feel betrayed by Trump on the ethanol issue was striking,” Sanford said. “The waivers are up, I think, 300 percent from the Obama years.” Asked if the government’s ethanol subsidies should exist at all, Sanford said they shouldn’t — but that Trump was the candidate who’d pandered to farmers in the 2016 caucus race against Sen. Ted Cruz of Texas. “I’m happy to learn more. That’s part of this is, if I become a candidate, I intend to learn a whole lot more.”

Iowa’s social conservatism, and the popularity of federal subsidies, were major impediments to any conservative challenger. Sanford couldn’t say how much he’d focus on the state, if he did run. His point was that he was not leaving it behind.

“We’ve seen the Giuliani example, and it doesn’t work,” said Sanford, referring to the former New York mayor’s strategic (and disastrous) retreat from early states to focus on Florida’s primary.

Like Walsh, and like former Massachusetts governor Bill Weld, who is running, Sanford said that any presidential campaign would focus on the long-term threat of deficits and debt. Sanford, like most Republicans, voted for the deficit-inflating 2017 tax cut; unlike Trump, he would offer Republicans a more austere fiscal policy. Without it, and with neither party focused on the deficit, he saw a growing, dangerous acceptance of running massive deficits.

“I think that there is an educational component that comes to any leadership role,” Sanford said. “One of my primary goals would be elevating this issue. I find it unfathomable that this issue is not being discussed in the presidential race. It’s not being discussed. I’ve watched the Democratic debates. It’s not not being discussed. On the Republican side, it’s sort of, ‘I hear no evil, I see no evil, I speak no evil.’ ”

Did it matter that Trump might be getting three challengers with identical messages on spending? Not to Sanford.

“I think it’s in the net good for all of us,” Sanford said. “If you’re talking about just one challenger, you can pretend to ignore it. If it’s Bill Weld and a couple of other guys, I think it becomes harder to dismiss it, or to shut down the primary process and end the debate that I think is needed within the Republican Party as to what it means to be a Republican these days.”

AD WATCH

Shirley Shawe, “Biden.” The first negative ad against Joe Biden, in Iowa, was paid for by the conservative Club for Growth. The second was paid for by Shawe, an investor with a long-running beef against Delaware’s court system, who plowed $500,000 of her own money into this spot, which calls the Chancery Court “too white and too male.” It also ropes in Elizabeth Warren, who has yet to introduce herself on Iowa airwaves, and who — while a critic of Biden’s senatorial career — has called for the ad to be taken down.

Dan Bishop, “Wrong Dan, Wrong Call.” This digital spot takes advantage of Democrat Dan McCready’s resistance to taking a position on a culture war question. Asked about the GOP legislature’s push to ban “sanctuary cities,” McCready told a radio interviewer that he was glad to see North Carolina Gov. Roy Cooper (D) veto it.

New Hampshire Democratic Party, “Corey Lewandowski Sells White House Access to Highest Bidder.” The Granite State’s Democrats fully expect the former Trump campaign manager to jump into the race for U.S. Senate, where Sen. Jeanne Shaheen is up for reelection. Their opening salvo against Lewandowski: attacking his well-covered use of Trumpworld access to make lucrative deals.

POLL WATCH

National head-to-heads (Quinnipiac, 1,422 registered voters)

Joe Biden — 54%
Donald Trump — 38%

Bernie Sanders — 53%
Donald Trump — 39%

Elizabeth Warren — 52%
Donald Trump — 40%

Kamala D. Harris — 51%
Donald Trump — 40%

Pete Buttigieg — 49%
Donald Trump — 40%

Every Democrat polling below Joe Biden has a problem: Democratic voters believe that he has the best chance to defeat the president. Every Democrat immediately below Biden now has polling that suggests they would start a general election with a lead, too. Quinnipiac, which often asks Democrats who they consider most “electable,” did not ask the question for this edition of the poll.

Michigan head-to-heads (EPIC-MIRA, 600 likely voters)

Joe Biden — 51%
Donald Trump — 41%

Elizabeth Warren — 49%
Donald Trump — 43%

Bernie Sanders — 48%
Donald Trump — 44%

Kamala D. Harris — 46%
Donald Trump — 43%

This is the first look at any Rust Belt state’s head-to-head polling since the start of summer and the first in Michigan since a Detroit News poll that found only Biden and Sanders with solid leads over Trump. EPIC finds that every Democrat, save Biden, is now viewed more negatively than positively in Michigan; all of them lead Trump, with Biden, Warren and Sanders leading outside the margin of error. Sanders’s “electability” push of two months ago had emphasized the old Detroit News poll; Warren’s campaign has generally stayed silent on individual polls.

IN THE STATES

North Carolina. The two Dans, McCready (D) and Bishop (R), met on Wednesday night in their only televised debate before the election. (Early voting started last week.) Seated next to each other, the two men made no surprise moves: Both shared their personal stories, and their attacks mirrored what they’d been running on TV. Bishop emphasized his public service and votes for bipartisan budgets; McCready emphasized his military service.

“I carried the military version of the AR-15 assault-style weapons for four years in the Marine Corps,” McCready said in a round about gun control, arguing for universal background checks. “I understand the seriousness that comes with handling firearms and the responsibility that comes with gun safety if it’s needed. But I’m also a father of four little kids. And ’m a Christian.”

Bishop, who has echoed third-party GOP advertising in attacking McCready’s solar energy investment, portrayed the Democrat as a kind of clean power grifter. 

“Your business is built on a special tax break,” Bishop said, “and in the process you caused a situation where electrical ratepayers pay a billion and a half dollars more over the last 10 years than they would have otherwise.”

McCready urged viewers to read a PolitiFact check finding Bishop's claim to be mostly false, then accused him of not wanting to “have the 30,000 cleaner new jobs that we do now.”

Bishop, who will campaign alongside the president right before Election Day, also waved off the moderators’ attempts to find distance between him and his party. Asked if farmers were being hurt by tariffs, Bishop said it was too early to quit the trade war: “They support President Trump’s policy of getting tough with China in particular,” Bishop said, “but they need for that policy to be brought to fruition and a successful conclusion relatively soon.”

Georgia. Sen. Johnny Isakson (R) announced this week that he will retire at the end of 2019, halfway through his third term. That will cue up a senatorial appointment for Gov. Brian Kemp (R) and a special election in 2020, giving Republicans two seats to defend in a state that has been inching left as the Atlanta suburbs get bluer. Former gubernatorial candidate Stacey Abrams has ruled it out, but a long list of Democrats are looking at it anew, from unsuccessful 2017 congressional candidate Jon Ossoff to 2014 Senate candidate Michelle Nunn. There had been a competitive primary underway for the state’s other Senate seat, held by Sen. David Perdue (R), who had defeated the moderate Nunn five years ago.

Mississippi. Republican Lt. Gov. Tate Reeves won his party’s nod to replace popular Gov. Phil Bryant, after a three-week runoff in which he accused his challenger of wanting to expand the left-wing welfare state by expanding Medicaid. In the first round, Reeves led former state Chief Justice Bill Waller Jr. by 15.6 points. He won the runoff by 8.6 points, as turnout fell for his campaign and as some reluctant Republicans got behind Waller. (Robert Foster, the northwest Mississippi legislator who ran third in the primary, endorsed Reeves’s challenger.)

2020

Before she was a campaign afterthought, Kirsten Gillibrand was one of the Democrats most widely seen as a potential future president. Elected to the House in the 2006 wave, reelected handily, then appointed to the Senate, Gillibrand struck observers as a smart and ruthless politician. After the 2016 election, she opposed more of the president’s nominees than any other Democrat, endorsed Medicare-for-all and aligned herself closely with the Women’s March.

Then came the campaign itself, in which none of this clicked. Gillibrand, who angered many high-dollar Democratic donors by urging former senator Al Franken to resign over allegations of sexual misconduct, never got another chance to introduce herself to liberals.

She tried everything — an early focus on family leave, a Midwest bus tour to highlight Trump’s “broken promises,” an emphasis on her gay rights victories that included marching through the Des Moines pride festival behind a transgender flag. But after a month-long blitz of digital and TV ads, she got no closer to reaching 2 percent in polls that would qualify her for the September debate.

Beto O’Rourke. He rolled out his first comprehensive trade strategy, which would end the president’s tariffs but otherwise be more market-friendly than most of what Democrats have proposed so far.

Tom Steyer. He released his past nine years of tax returns, revealing that he made $959,500,000 in pretax income, and he criticized the DNC while saying he intended to make the October debates. (He needed just one more poll showing him at 2 percent or better to qualify.) “We do hope that the Democratic National Committee expands their polling criteria in the future to include more early state qualifying polling,” Steyer said.

Bernie Sanders. He released the second in what’s become a series of friendly interviews with rappers who support his campaign; the latest, with Killer Mike, focuses on what Sanders’s agenda would do to eliminate health disparities and what it takes from Martin Luther King Jr.’s final campaign.

Andrew Yang. His supporters made the term #YangBlackOut trend after a CNN graphic cut him out but left in the lower-polling Beto O’Rourke. 

Kamala D. Harris. She scrapped and could not reschedule an interview with the Working Families Party, which has been holding one-on-one talks with candidates ahead of its planned September endorsement vote. That removed her from the WFP’s consideration.

DEMS IN DISARRAY

Data for Progress, a liberal think tank that often partners with YouGov Blue to test different policies’ popularity, came back from the field with bad news. Two ideas — one endorsed by a number of Democrats running for president and one pitched off the cuff by Michigan Rep. Rashida Tlaib — were both incredibly unpopular.

The first question, asked of 1,380 voters, focused on the text of the Senate’s Medicare-for-all bill: Would voters like to see “all adults in the United States eligible for Medicare if they qualify, including legal immigrants and undocumented immigrants?” Just 34 percent of voters were on board; 50 percent opposed it, and 41 percent did so strongly.

The second question, posed to the same sample, was about a comment Tlaib made at one of her Detroit-area town halls: Should the minimum wage be raised not just to $15, but $20? The results were nearly identical: 34 percent of voters endorsed the higher wage and 49 percent opposed it.

“Data for Progress seeks to describe the world as it is, and fight for the world we want,” said Data for Progress co-founder Sean McElwee, who earned national attention for the slogan “abolish ICE” — something Democrats have largely stopped saying. “There are some progressive ideas that are no doubt out of the mainstream, and we aren’t afraid to say when they are.”

COUNTDOWN

... six days until the CNN climate town halls.
... nine days until the New Hampshire Democrats’ state convention.
... 14 days until the third Democratic debate.