Former vice president Joe Biden is still near the top of the field in Democratic primary polling. He still enjoys the support of 1 out of every 5 primary voters, not a bad place to be if you’re running in a crowded field.

But these are snapshots of a campaign that’s headed rapidly downward. If Biden’s team is able to turn things around, it would be one of the more remarkable reversals in presidential primary history.

For the second time in two days, a new national poll showed Biden’s support collapsing: On Monday, a poll came from Quinnipiac University, and that could have been considered a possible outlier. On Tuesday, it was Monmouth University echoing the Quinnipiac findings and suggesting there’s a real phenomenon underway.

The dark blue line on the graphs below represent Biden. His support from primary voters was cut in half between Monmouth’s January and February polls. His net favorability — the percent viewing him favorably minus those viewing him unfavorably — has been trending downward for three months. Sen. Bernie Sanders (I-Vt.), on the other hand, has seen a steady increase in support and a consistent net favorability.

As in the Quinnipiac poll, Biden is seeing big drops in support from demographic groups that were solidly supportive of his campaign. Among nonwhite Democratic primary voters, for example, Biden trails Sanders by eight points. Among moderates, he leads Sanders by only three points.

Sen. Elizabeth Warren (D-Mass.) also saw a drop in support in Monmouth’s poll over time, but hers was neither as sudden as Biden’s nor as recent. Her net favorability, like Sanders’s, is higher than Biden’s.

In October, Warren looked like she might overtake Biden, who had enjoyed a steady lead in primary polling. But her surge began to slip soon after she matched Biden’s position in the RealClearPolitics polling average. Biden’s support had risen and fallen, over and over, little by little, and Warren couldn’t stay with him. In the past week or two, though, Biden’s support has fallen off a cliff.

Notice where the support has increased as Biden has fallen. Sanders has gained a bit over a slightly longer time frame. But the two candidates who have directly surged in correlation to Biden’s plunge are former South Bend, Ind., Mayor Pete Buttigieg and former New York mayor Mike Bloomberg.

In the past two weeks, Biden has lost about nine points in the polling average, while Bloomberg and Buttigieg have each gained a bit over 4.5 points. Those changes are probably connected.

If we look at the field as primarily consisting of two types of candidates — progressives vs. moderates — that shift makes more sense. Sanders and Warren have earned an average of about 36 percent of the vote since the beginning of the year while Biden and other more moderate candidates have combined for about 46 percent.

Two weeks ago, Biden, Bloomberg, Buttigieg and Sen. Amy Klobuchar (D-Minn.) combined for 47.2 percent of the total primary support. Now, they combine for 48.4 percent — even as the composition of that support has changed dramatically.

Part of the change in Biden’s fortunes is a function of his poor showing in Iowa. When Hillary Clinton came in third in that state’s caucuses in 2008, she rebounded with an unexpected win in New Hampshire. That doesn’t seem to be in the cards for Biden, who has repeatedly telegraphed an expectation he would fare poorly in Tuesday’s primary. His team had hoped he could weather the first two contests and rebound with strong showings in South Carolina and Nevada.

That strategy may have paid too little consideration to Biden’s primary value proposition: He was the guy who could win against President Trump. Sure, facing off against other Democrats isn’t quite the same thing, but losing elections isn’t a great way to bolster the idea that you’re good at winning them.

Biden hasn’t yet hit the end of the road, but he’s accelerating in that direction.