As third phase of the Democratic race begins, Sanders and Biden remain the fixed poles

Thursday night’s Democratic debate marked the start of the third phase of the race for the presidential nomination.

The first phase, introductions, started just under a year ago and saw the field of candidates reach a record size. The winnowing phase began with the first debates, spread over two nights in June. Gradually, candidates either dropped out or faded into irrelevance, leaving the seven who debated Thursday, plus a couple more, like Sen. Cory Booker of New Jersey and former Mayor Michael Bloomberg of New York, who weren’t on stage but can’t be completely discounted.

This third phase will last through the early primaries. If Democrats are lucky, one candidate will quickly emerge as a strong voter favorite, consolidate support and begin focusing on the general election battle with President Trump. If not, they’ll face a long, potentially debilitating, slog that could last into the nominating convention in July.

TWO POLES AND A LOT OF CHURN

Although the last year has seen many ups and downs, a dominant feature of the race has been the presence of two fixed poles: Sen. Bernie Sanders and former Vice President Joe Biden. The two started the year at the top of the field in national surveys and, except for a stretch this fall when Sen. Elizabeth Warren moved past Sanders into second place, they have remained there ever since.

The race’s other dominant feature has been a large pool of voters who haven’t been satisfied with either of the two septuagenarian, white men and have churned among other candidates, briefly lifting Sen. Kamala Harris into prominence, then boosting Warren and more recently South Bend, Ind., Mayor Pete Buttigieg.

Both Harris and Warren went through a familiar cycle — rising in the polls, attracting more scrutiny and then losing ground as a result. Buttigieg may be moving onto the down part of the roller coaster now. As Melanie Mason reported, his rise has generated outrage among many in the party’s left wing.

Harris never recovered from her slide; Warren hopes to pull out of hers. Supporters of Sen. Amy Klobuchar of Minnesota, who received strong reviews during and after Thursday’s debate, hope her turn will come, just in time for the actual voting.

Sanders’ supporters, many of whom grew devoted to him four years ago, are especially notable for their tenacity. In that regard — if nothing else — his backing resembles Trump’s. If a heart attack in a 78-year-old candidate isn’t enough to shake support for a candidate, what plausible events would?

The challenge for Sanders, much as it was four years ago when he ran against Hillary Clinton, is to expand beyond his base of the young, the left and the disaffected. So far, he hasn’t done that. His support remains solid but largely fixed.

Dave Peterson of Iowa State University analyzed four months of data from the Iowa State/Civiqs poll of likely voters in the state’s Feb. 3 caucus, looking at the many voters who have switched among the leading candidates.

“Sanders seems to be an island. Voters shift between the other candidates, but not Sanders,” he wrote. The Vermont senator has picked up some support as second- and third-tier candidates have faded, but a large majority of his voters have been with him from the outset.

Biden stands at the opposite poll, both ideologically and in fervor of support. His voters can often sound more resigned than enthusiastic, and he has lost a fair amount of ground since his peak, when he entered the race this spring. Because black voters form a major part of his voting base, he has suffered in polls of Iowa and New Hampshire, where the voting population is nearly all white.

Despite all that, he remains at the front in national surveys.

Early in the summer, many people guessed that Biden’s path would point steadily downward. Rivals such as Harris built their strategies on that assumption. It didn’t happen. Instead, Biden’s support stabilized this fall, and as Thursday’s debate showed, his performance as a candidate has improved.

It’s possible that Biden could now regain some of the backing he lost over the summer, enough to win Iowa or at least finish strongly and position himself for big victories in subsequent contests. Biden’s not a dominant front-runner, but if that happens, he has potential to quickly wrap up the nomination. A year into the contest, it’s not clear that any of his rivals can make the same claim.

THE IMPEACHMENT FACTOR

The House vote Wednesday to impeach Trump had the odd dual quality of feeling historic, yet leaving the political world largely unchanged. As Janet Hook and Evan Halper wrote, the candidates have been eager to talk about almost anything other than impeachment, and in the debate, they fumbled around when asked why the country remains so divided on the issue.

“It is already priced into the stock,” as Brian Fallon, the former spokesperson for Clinton, put it, explaining why talking about impeachment does little to help Democratic candidates.

For House Speaker Nancy Pelosi, impeachment will define her legacy, as Jennifer Haberkorn wrote. If the Democrats win in November, she’ll receive a share of the credit. If they lose, she, and her decision to push ahead with the impeachment, will get blamed.

As for the candidates, impeachment could affect their race in a couple of ways:

A Senate trial of Trump is still likely to take place in January, despite Pelosi’s decision to slow-walk the process of delivering the House impeachment resolution to the Senate, as Sarah Wire reported. That would require the senators in the race to stay in Washington for a couple of weeks during peak campaign season — a disadvantage for Warren and Klobuchar, in particular.

Perhaps more important, the fact that impeachment has not changed anything — Trump remains deeply unpopular in much of the country, but strongly supported among Republicans — has redoubled the attention Democrats already were giving to who has the best shot at beating him next year. As Janet Hook wrote in her analysis, the theme of electability ran through Thursday’s debate.

Who can actually win is always a central question in primaries, but it has dominated this year’s race to an unusual extent. With the House impeachment debate over, and Trump still in a dead heat with the potential Democratic nominees in key states, that focus will only intensify.

Meantime, as Eli Stokols reported from Michigan, where Trump held a rally the night of the House vote, the president has made clear that he hopes to make running against impeachment a central theme of his campaign.

As Noah Bierman and Chris Megerian wrote, “Trump has treated the stain of impeachment as he has every other scandal and crisis in an administration that is whipsawed by them — by lashing out at enemies, spewing personal insults, refusing to express remorse and claiming he is a victim of a partisan injustice.” Impeached but unchastened could be his reelection slogan.

And as Jenny Jarvie predictably found in rural Georgia, his core supporters are openly dismissive of the entire matter.

NEED A CATCH-UP ON THE DEBATE?

Our L.A. Times politics team has you covered. Melanie Mason recapped the key moments as the debate brought long-simmering rivalries into the open, and Mark Barabak offered his five takeaways. In a bit of counter-programming, Julián Castro, who didn’t qualify for the debate, spent the day before touring Los Angeles’ skid row to emphasize his experience dealing with issues of homelessness, Melissa Gomez reported.

TWO BIG NEWS STORIES THAT GOT OVERSHADOWED

The federal appeals court in New Orleans took months to rules in a case that once again challenged the constitutionality of the Affordable Care Act, and when they did, their ruling largely punted. The court said that the law’s requirement that people buy insurance — which has already been rendered a nullity by Congress — was unconstitutional. But the judges didn’t decide the bigger question of what other parts of the law might be invalid.

The net result is to keep Obamacare alive but under threat. That means its fate once again will be hanging in the balance in the election. In 2018, Democrats used that peril effectively as a campaign weapon against Republicans. This year, however, they’ve spent much more time arguing among themselves about Medicare for all.

And the House overwhelmingly passed the USMCA, the trade agreement with Canada and Mexico that updated NAFTA. The trade deal passed with support of both Trump and Pelosi, along with much of organized labor. As Don Lee wrote, it marks a major shift away from free-trade policies of the last several decades.

A HEAD-SPINNING YEAR

Covering Trump can induce vertigo, as scandals, squabbles, outrages and accidents swirl by with bewildering speed. Eli Stokols captured the dizziness well in his year-end essay on his year of covering the Trump White House.

LOGISTICS

That wraps up this week.

We’ll be off next week and hope you all enjoy the holidays. The Essential Politics newsletter will return Dec. 30. Until then, keep track of all the developments in national politics and the Trump administration on our Politics page and on Twitter @latimespolitics.

Send your comments, suggestions and news tips to politics@latimes.com.

If you like this newsletter, tell your friends to sign up.

david.lauter@latimes.com