I’m writing this on Thursday morning, before there’s much, if any, polling available that reflects how Democrats’ preferences changed following the two-night presidential debate this week. But even before the debate, some candidates had been on the move in the three weeks since my last comprehensive assessment of the Democratic field.

So let’s do another installment of my not-to-be-taken-too-seriously presidential tiers, based on polling shifts over the past few weeks, an evaluation of who’s likely to qualify for the third Democratic debate in September, and my initial impressions of the debate this week.

Nate’s not-to-be-taken-too-seriously presidential tiers For the Democratic nomination, as revised on Aug. 1, 2019 Tier Sub-tier Candidates 1 a Biden b Warren, Harris ↓ 2 a Sanders b Buttigieg, Booker ↑ 3 a Klobuchar ↑, Castro ↑ b O’Rourke, Yang ↑ 4 a Bullock ↑, Inslee, Gillibrand, Gabbard ↑ b Everyone else

First things first: Joe Biden is pretty clearly out in front, so I don’t quite get why prediction markets only have him in a rough tie with Kamala Harris and Elizabeth Warren. Pre-debate, he led his nearest competitors (Bernie Sanders and Warren) by 16 to 17 points in the RCP polling average, a margin that’s nothing to be sneezed at given the historical accuracy of primary polls at this stage. And he’s shown some resilience, having already bounced back in the polling average to where he was before the first debate, and then having had a second debate which — while it wasn’t great, in my view — was better than the first one despite a lot of incoming fire from other Democrats. I’m still a seller of the proposition that Biden is an odds-on favorite to win the nomination — that is, I think his chances are under 50 percent. But I think he’s more likely than anyone else.

With that said, I’d keep an eye on Warren, whose strong first-night performance looks better by comparison after a series of uneven evenings for the Democrats last night. She has a clearer message than Harris, and she makes for a sharper contrast to Biden, whom she hasn’t had a chance to share a debate stage with yet.

For that matter, I am almost tempted to say that Sanders’s chances have become underrated if prediction markets have him at under 10 percent to win the nomination. (He’s been hovering at between 6 percent and 9 percent in recent days at Betfair.) I think Sanders has quite a lot of issues that limit his upside, but those seem to be priced into the conventional wisdom about his chances in a way they weren’t before. And I thought Sanders had a pretty good debate. I’m keeping him at the top of Tier 2 for now, but he’s poised to move back into Tier 1 if the next few polls showing him gaining ground.

I do have Cory Booker moving up a tier, from Tier 3 to Tier 2. He was maybe the strongest performer last night from start to finish, he’s been getting more media attention, and he’s poised to benefit from any loss of support from Harris.

In the lower tiers, it’s mostly a matter of which candidates are actually likely to make the debate stage next time around, something that Amy Klobuchar, Julián Castro, Beto O’Rourke and Andrew Yang can probably be more confident about than any of the others. Sure, Yang would be a less traditional nominee than the rest of the group. But all of these folks are polling at 1 to 3 percent, so putting him in this group isn’t exactly showering him with praise. And I thought he and Castro had stronger debates than Klobuchar and O’Rourke.

If I had to pick someone from among the Tier 4 candidates, it would probably be Montana Gov. Steve Bullock, who was among the stronger performers on Tuesday night, and who has a variety of interesting attributes (electability, executive experience, a mix of moderation and economic populism) that differentiate him from the field. But he’s far from qualifying for the next debates, so he’s going to have to find some way to command attention in what could be a slow period for the campaign.