Since last week’s Democratic debate, political observers have been keenly awaiting the results of the latest round of polling, and we now have plenty of new data to chew on. Five national polls this week indicate that Joe Biden has retained his lead in what looks like a three-horse race—and his numbers have actually moved up a bit. Elizabeth Warren remains in second place, but a new poll indicates that she is in the lead in Iowa, where the 2020 primary will begin. Bernie Sanders retains a good deal of support nationally, too, although his path to the nomination looks increasingly challenging. Everybody else is still way back.

In the past few days, Politico/Morning Consult, NBC News/the Wall Street Journal, SurveyUSA, The Economist/You Gov, and Fox News have each released national polls. Biden was ahead in all five of them, and in three the margin was double digits. On Thursday morning, the former Vice-President was 10.5 percentage points ahead of Elizabeth Warren in the Real Clear Politics poll average, which combines the results of a number of individual surveys, and 12.3 points ahead of Bernie Sanders. (The next closest challenger, Pete Buttigieg, was more than twenty points behind Biden.)

There’s an old saying in polling that you should follow the trend. On August 19th, the R.C.P. poll average showed Biden’s support at 28.8 per cent; on September 12th, he was at 26.8 per cent; on Thursday morning, he was at twenty-eight per cent. The trend line has moved down in the past month, but in the past week it has edged up, despite the post-debate controversy about Biden’s rambling (and, in the view of some commentators, racist) answer to a question about reparations. As SurveyUSA noted when releasing its results, “Record player or no record player, Joe Biden remains Joe Biden at this hour, drawing 33% of the vote in a crowded field, almost exactly as he has done in previous SurveyUSA polling.”

Breakdowns of the Democratic electorate, including one from The Economist that is particularly easy to follow, show Biden with a substantial lead among moderates, older voters, black and Hispanic voters, and people who didn’t attend college. Among voters under forty-five and those with college degrees, Warren and Sanders are both ahead of him. Despite his gaffes, Biden remains well ahead on the question of perceived electability. According to the SurveyUSA poll, forty-five per cent of likely Democratic Primary voters think that Warren would defeat Donald Trump in the general election, and forty-three per cent think that Sanders would win. Sixty-one per cent of respondents think that Biden would beat Trump.

The immediate challenge to Biden isn’t that his support is dropping nationally but that Warren is consolidating support from voters who previously expressed preferences for candidates outside the top three or who weren’t sure whom to back. The Massachusetts senator has been trending up since April. In the NBC News/Wall Street Journal poll, her support has jumped six points since July, from nineteen per cent to twenty-five per cent. Biden’s numbers are up in this poll, too, and Sanders’s support has stayed pretty steady. Warren appears to have picked up most of her newfound supporters from Kamala Harris and out of the “Not sure” category. Harris has tumbled from thirteen per cent to five per cent. The tally of undecideds has fallen from eight per cent to two per cent.

The latest polls from Iowa, where the caucuses will be held on February 3rd, illustrate Warren’s momentum at the local level. In a survey of likely caucus goers by Iowa State University/Civiqs, twenty-four per cent of the respondents expressed support for Warren, compared to sixteen per cent for both Biden and Sanders. The second poll, from Focus on Rural America, showed Biden leading Warren by the narrow margin of twenty-five per cent to twenty-three per cent, with Pete Buttigieg in third place, at twelve per cent. If Warren were to win in Iowa and New Hampshire, where she also appears to be making up ground, she would obviously be in a very strong position.

Campaigns, in gauging their candidate’s progress, don’t merely look at the headline figures from the polls. They monitor all sorts of things, including the amount of excitement about their candidates and the size of their potential voter pools. In the NBC News/Wall Street Journal poll, thirty-five per cent of respondents registered enthusiasm about Warren, compared to twenty-five per cent for Sanders, and twenty-three per cent for Biden. Potential reach is a bit trickier to measure. The Economist/YouGov survey asked people to list all the candidates whom they were considering voting for. Fifty-three per cent of respondents included Warren on their list, fifty-one per cent included Biden, and forty-one per cent included Sanders. Both of these findings suggest that Warren’s campaign may have the most room to grow.

At a moment when Sanders is overhauling his campaign’s leadership in Iowa and New Hampshire—and the site PredictWise is giving him just a one-in-nine chance of winning the nomination—he will also take some encouragement from the latest national polls. Three months ago, on June 19th, the R.C.P. poll average had Sanders at fifteen per cent; on Wednesday, he was at 16.3 per cent. In two of this week’s national surveys—those from Politico/Morning Consult and Fox News—Sanders was in second place, narrowly ahead of Warren. An Emerson poll in California showed him tied for the lead with Biden, although another California survey showed Biden with a nine-point advantage.

One message from these polls is that Sanders still has a firm base. His supporters tend to be younger, less affluent, and less firmly attached to the Democratic Party than Warren’s supporters are. The challenge facing Sanders, a formidable one, is to expand beyond his core when so many self-identified liberal Democrats are backing Warren—thirty-six per cent in the NBC News/Wall Street Journal poll. He’s certainly trying. On Wednesday, he rolled out a $2.5 trillion “Housing for All” plan, which includes building more affordable housing, expanding rental assistance, and introducing a national rent-control standard.

Taken together, Warren and Sanders now have quite a bit more support than Biden does, the polls suggest. Among younger and college-educated voters, it’s not even close. (In the under-thirty demographic, just nine per cent favor Biden, according to The Economist’s analysis.) When Warren appeared on Rachel Maddow’s MSNBC show on Tuesday night, the host asked how Warren and Sanders could avoid splitting the progressive vote and allowing a more centrist candidate to get the nomination. Warren said that she’d “been friends with Bernie what feels like forever” and added that competition was healthy. That didn’t really answer the question. In the past few weeks, there has been a lot of attention paid to the Biden-Warren matchup. Going forward, the Warren-Sanders dynamic could be equally important.