Plenty of people were all but writing off Joe Biden after his bad finishes in Iowa and New Hampshire. He is still counting on the South Carolina primary. But there were real questions about whether he’d even be relevant by the time it rolled around, as other moderate-ish candidates showed momentum and his long-standing lead in the Palmetto State narrowed.

Things are looking quite a bit rosier for former vice president Biden now in the Democratic presidential contests. And there’s reason to believe he could soon emerge as the chief alternative to Sen. Bernie Sanders in 2020.

A Monmouth University poll released Thursday became the latest to show Biden reasserting a big lead in South Carolina. It has him leading Sanders by a whopping 20 points — 36 percent to 16 percent. Public Policy Polling also has him up 15.

That’s a very different state of affairs from after the New Hampshire primary. After Biden’s fifth-place finish there, five successive polls showed him between tied with Sanders and with a five-point lead. And after Sanders’s resounding win in Nevada, it looked like he might be in line for a kill shot — not just for Biden, but perhaps for the rest of the field — in South Carolina. Should Sanders win South Carolina somehow, that would be four popular-vote wins in four states and a big one in a heavily African American Democratic primary. That would mean Biden loses a state that he quite simply needs to win to have any shot.

South Carolina voters, though, seem to have had another idea. The Monmouth poll, in particular, suggests that Biden’s win in South Carolina could be resounding. That’s because he’s not just up 20 points, but the undecided voters appear very get-able for him. While just 8 percent of white voters are undecided, 17 percent of black voters remain in play. And Biden just got a coveted endorsement from the highest-ranking black member of the U.S. House, Majority Whip James E. Clyburn (D-S.C.).

“A key metric for Biden in this make-or-break state is that his support appears to be firm,” Monmouth polling Director Patrick Murray said. “There is still a large chunk of the electorate who are undecided, but they are mainly moderate black voters. That’s a group that tends to like Biden.”

Perhaps as encouraging for Biden is how the rest of the field is shaking out — both in South Carolina and elsewhere. The third-place candidate in basically every recent South Carolina poll is Tom Steyer, who pulled 15 percent in the Monmouth poll and 17 percent in the Clemson poll. All the other candidates are pretty much nowhere to be seen: Sens. Elizabeth Warren and Amy Klobuchar and former South Bend, Ind., mayor Pete Buttigieg are all consistently in the single digits there.

Barring a late shift, that would mean those three won’t exactly be riding high heading into Super Tuesday, which is three days after South Carolina. (Only Buttigieg managed double digits in Nevada, but he’s still lagging in the national polls.) And to the extent Klobuchar and Buttigieg aren’t viewed as viable, that could quickly accrue to Biden’s benefit. That’s because they appeal to the more moderate side of the Democratic Party, and there isn’t really much time (or money, in many of their cases) to change things between South Carolina and Super Tuesday.

If that comes to pass — and to be clear, this is playing around with hypotheticals — Biden’s biggest obstacle to turning this into a two-horse race Tuesday would seem to be Mike Bloomberg. Bloomberg will be on the ballot for the first time there, and he has put himself in a decent position by dumping hundreds of millions of dollars on these states, largely uncontested.

But a rough debate for Bloomberg last week appears to have sapped his momentum somewhat in national polls. He’d been on a clear upward trajectory, but it’s now stopped — if not reversed a bit. Super Tuesday polling is unfortunately very limited, so we don’t really know whether that’s the case in those particular states, and it could be different given how many Bloomberg ads people in them are seeing. But while Bloomberg was looking like the moderate, electability candidate for a while, you do wonder if the confluence of circumstances after South Carolina could make Biden that candidate and help him beat Bloomberg on Super Tuesday.

Bloomberg campaign manager Kevin Sheekey downplayed that possibility of Biden grabbing momentum in South Carolina on Thursday morning, telling MSNBC, “Obviously it’d be an enormous blow to the vice president if he lost or just won by a little. But either way, South Carolina is not going to matter — it doesn’t appear to me that anyone is gonna get out of this race before that.”

Even if all of this comes together for Biden, though, that doesn’t mean he’s set. He succeeded in this week’s debate largely because the other candidates left him alone and he was able to drive a message — one that was focused on black voters who will be big factors not just in South Carolina, but in many states that are voting on Super Tuesday. If he wins South Carolina big and is a real contender after Super Tuesday, the pressure will be on again. And Biden hasn’t exactly handled the pressure well.

His candidacy also continues to feature major questions. Just this week, The Washington Post’s Fact Checker gave him four Pinocchios for his noncredible claim to have been arrested trying to see Nelson Mandela in South Africa. It wasn’t a huge story, but if he’s back in contention, it certainly would be. He’s also been a thoroughly unsteady candidate, which seems to be part of the reason he faded in the first place.

In other words, a big win in South Carolina and a strong Super Tuesday wouldn’t be a cure-all for Biden. But it’s the opening he hoped for earlier this month, and it wasn’t clear it would be there a few weeks ago.