Joe Biden didn’t get off to the start his campaign was hoping for in Iowa and New Hampshire. But the news has been better for him lately. He finished a (distant) second place in Nevada behind Bernie Sanders, his best performance of the campaign so far. And his polling in South Carolina has held up well, potentially positioning him for his first win.

As of early Wednesday afternoon, Biden is at 31.1 percent in our South Carolina polling average, giving him roughly a 10-point lead over Sanders, who is second with 21.4 percent. Tom Steyer is third at 14.6 percent, with everyone else in the single digits. If Sanders was hoping for a post-Nevada bounce, it doesn’t seem to be happening in the Palmetto State. The most recent polls for Biden, which conducted all or some of their interviews after Nevada, actually show him with a larger lead over Sanders than the ones before Nevada. And none of the polls yet account for House Majority Whip James Clyburn’s endorsement of Biden.





How Rep. James Clyburn settled on endorsing Joe Biden for president

Still, 10-point polling leads in the primary are not entirely safe, especially with several days left to go until a state votes. So let’s look at how our forecast model views three plausible scenarios: a big Biden win (by 10 percentage points or more), a modest Biden win (by less than 10 points) and a Sanders win (no margin specified). As of Wednesday afternoon, the chance of these outcomes happening according to the model was 41 percent (big Biden win), 33 percent (small Biden win) and 23 percent (Sanders win), respectively. We won’t consider the outside possibility (3 percent) of a Steyer win.

In the model, performing strongly in states helps candidates for several reasons. For example, since the outcome in each state is partially correlated, if Biden does well in South Carolina, that would also be a favorable sign for him in other Southern states, a number of which vote on Super Tuesday.

But the most important mechanism is a polling bounce. That is, after you win a state, it tends to produce favorable media coverage and improve voter confidence in your chances, usually producing a rise in the polls. The model does not necessarily expect South Carolina bounces to be especially large; South Carolina doesn’t receive nearly as much media coverage as Iowa or New Hampshire. But even a modest bounce for Biden could make a fairly big difference in the overall picture of the race. And an emphatic Biden win in South Carolina would leave open the possibility of a bigger bounce. Let’s talk about that case first.

A big Biden win could reorder the race



Rather than project all the way through the end of the primaries — we’ll save that for later — I’m going to restrict our focus to what happens on Super Tuesday depending on these three South Carolina scenarios. Here, according to our model, is what the post-Super Tuesday delegate count could look like following a big Biden win in South Carolina. Keep in mind that these represent the average of thousands of simulations; individual outcomes will vary based on factors such as Biden’s margin of victory in South Carolina, whether anyone drops out before Super Tuesday, and so on.

Scenario 1: Super Tuesday after a big Biden win in S.C. Average number of delegates candidates win (or have won) in each state based on an average of 4,100 simulations of the FiveThirtyEight primary model as of Feb. 26 at 2 p.m. State Sanders Biden Bloomberg Warren Buttigieg Klobuchar Iowa 12 6 0 8 14 1 N.H. 9 0 0 0 9 6 Nev. 24 9 0 0 3 0 S.C. 14 31 0 1 1 0 Calif. 207 102 37 49 19 2 Texas 76 84 40 19 7 1 N.C. 32 42 26 6 3 1 Va. 31 33 25 3 6 1 Mass. 32 16 8 25 8 1 Minn. 26 8 1 8 3 29 Colo. 32 14 8 9 4 0 Tenn. 17 25 15 5 2 0 Ala. 10 27 12 2 1 0 Okla. 9 12 10 3 2 0 Ark. 8 10 8 1 3 0 Utah 16 4 4 4 1 0 Maine 10 4 4 3 3 0 Vt. 13 1 1 1 1 0 A.S. 2 2 1 1 0 0 Total 578 430 200 148 92 44 Pct dels 39% 29% 13% 10% 6% 3% We’re defining a “big” Biden win as 10 percentage points or more. Tom Steyer and Tulsi Gabbard are not listed as they are projected to receive a negligible amount of delegates.

An outcome like the one in the table wouldn’t be a disaster for Sanders, by any means. He’d still be projected to end up with 578 delegates, on average after Super Tuesday, counting both delegates won before Super Tuesday and on Super Tuesday itself. In other words, Sanders would still pick up 39 percent of the total delegates awarded so far. Biden would be next with 430 delegates (29 percent), with Michael Bloombeg in third with 200 delegates (13 percent).

But you can also see how momentum could start to turn against Sanders. By “momentum,” I don’t mean something ineffable, but rather the shifts in the polls that could occur as the result of Super Tuesday, as well as decisions by other candidates to stay in the race or drop out.

In the scenario above — after a big South Carolina win — Biden would be the plurality favorite in every Southern state on Super Tuesday, namely: Texas, North Carolina, Virginia, Tennessee, Alabama, Oklahoma and Arkansas. While Sanders would remain the favorite in every non-Southern state except Minnesota including — critically — California, where he has a huge polling lead and where 415 pledged delegates are at stake.

But even if Sanders racks up big margins in California, this isn’t a great outcome for him from a delegate standpoint. He’d only be about 150 delegates ahead of Biden out of a total of 3,979 pledged delegates eventually to be awarded.

And from a narrative standpoint — and the polling bounce that results from it — it could be fairly bad for him. Sanders might not get very many wins in the Eastern and Central time zone states that the media will cover heavily early in the evening. And the wins Sanders would get would mostly be in white, liberal states where he was expected to win — until California reports its results, but that creates its own problems for Sanders.

What’s wrong with California? Well, nothing, nothing at all. But California takes a long time — days and sometimes even weeks! — to count its votes since mail ballots there only need to be postmarked by Election Day. Moreover, those late returns often shift the margins toward candidates such as Sanders who do well among younger voters, since younger voters are typically slower to send in their ballots. Thus, the Super Tuesday media narrative could already be written by the time California reports reliable results, and the initial returns in California might underestimate Sanders’s eventual vote share there.

Moreover, in this scenario, commentators could rightly point out that Biden and Bloomberg had more combined delegates (630) than Sanders (578). Furthermore, the broader moderate lane — Biden, Bloomberg, Buttigieg and Amy Klobuchar — would have more combined delegates (766) than Sanders and Warren (726). That could give credence to the theory that the majority of Democrats did not want a nominee as progressive as Sanders.

Furthermore, those theories about “lanes” could finally be put to the test because other candidates might finally drop out after Super Tuesday. In this scenario, Biden would be a rather clear No. 2 to Sanders and nobody apart from Sanders and Biden would have an obviously viable path to the nomination. So Biden could gain further ground from Bloomberg, Buttigieg and Klobuchar voters joining his camp if those candidates quit the race.

What’s more, the rest of the March calendar contains a lot of states that look pretty decent for Biden (Florida, Georgia, Missouri, Mississippi) or at least highly competitive between he and Sanders (Illinois, Ohio, Michigan, Arizona). You’d still probably rather be Sanders than Biden. But it would turn the nomination into a highly competitive race.

A narrow Biden win would leave him with some work to do



What if Biden wins South Carolina, but by a narrower margin? On the surface, it’s not that different from the scenario above. But a slightly smaller Biden bounce as opposed to a slightly larger one would allow Sanders to breathe a lot easier.

Scenario 2: Super Tuesday after a modest Biden win in S.C. Average number of delegates candidates win (or have won) in each state based on an average of 3,300 simulations of the FiveThirtyEight primary model as of Feb. 26 at 2 p.m. State Sanders Biden Bloomberg Warren Buttigieg Klobuchar Iowa 12 6 0 8 14 1 N.H. 9 0 0 0 9 6 Nev. 24 9 0 0 3 0 S.C. 18 24 0 2 1 0 Calif. 219 87 39 48 20 2 Texas 84 74 42 19 7 2 N.C. 37 35 27 6 4 1 Va. 34 28 26 3 7 1 Mass. 34 14 9 24 9 1 Minn. 28 6 1 8 3 29 Colo. 33 11 8 9 4 0 Tenn. 20 21 15 5 2 0 Ala. 13 22 13 3 2 0 Okla. 11 10 11 3 2 0 Ark. 9 8 9 2 4 0 Utah 17 3 4 3 1 0 Maine 10 4 4 3 3 0 Vt. 13 0 1 1 1 0 A.S. 2 2 1 1 0 0 Total 628 364 210 146 96 45 Pct dels 42% 24% 14% 10% 6% 3% We’re defining a “modest” Biden win as less than 10 percentage points. Tom Steyer and Tulsi Gabbard are not listed as they are projected to receive a negligible amount of delegates.

Rather than trailing Sanders by about 150 delegates after Super Tuesday as in the first scenario, Biden would trail by around 260 delegates in this one. And Sanders would remain the favorite — although a narrow favorite — in Texas, North Carolina and Virginia, instead of having become an underdog in those states. Furthermore, the combined moderate lane delegate counts would longer exceed the progressive lane counts (Sanders and Warren together would have 52 percent of delegates to the moderates’ 47 percent), depriving Biden of that talking point.

What this leads to, most likely: Biden would be viable, but he would need some other breaks, namely (i) the other moderates to drop out and (ii) a really strong performance in the remaining March contests. And his goal would probably be to secure a plurality of delegates — or to at least get to a contested convention — with a majority being more of a long shot.

If Sanders wins South Carolina, he’ll be in great shape



Finally, what if Sanders wins South Carolina? Well, we’ll run through this quickly, because it’s exactly what you’d think: GREAT NEWS FOR BERNIE.

Scenario 3: Super Tuesday after a Sanders win in S.C. Average number of delegates candidates win (or have won) in each state based on an average of 2,300 simulations of the FiveThirtyEight primary model as of Feb. 26 at 2 p.m. State Sanders Biden Bloomberg Warren Buttigieg Klobuchar Iowa 12 6 0 8 14 1 N.H. 9 0 0 0 9 6 Nev. 24 9 0 0 3 0 S.C. 26 18 0 1 2 0 Calif. 254 50 44 43 21 3 Texas 105 50 47 17 8 2 N.C. 49 22 29 5 4 1 Va. 44 17 27 2 7 1 Mass. 41 7 10 22 9 1 Minn. 33 2 2 6 3 28 Colo. 39 6 9 8 5 0 Tenn. 28 13 16 4 2 0 Ala. 19 15 13 2 2 0 Okla. 14 6 11 2 2 0 Ark. 13 4 9 1 4 0 Utah 18 1 4 3 1 1 Maine 12 2 4 3 3 0 Vt. 13 0 1 1 1 0 A.S. 3 1 1 1 0 0 Total 757 230 228 131 99 46 % of Dels. 50% 15% 15% 9% 7% 3% In a Sanders’s South Carolina win, no margin is specified. Steyer and Gabbard are not listed as they are projected to receive a negligible amount of delegates.

After winning South Carolina, Sanders would be projected to end up with just slightly more than half of all the pledged delegates after Super Tuesday. Moreover, there would be no clear alternative to him. Biden would be devastated by the South Carolina loss and might drop out. (Although with only three days between South Carolina and Super Tuesday, that might make it less likely than it would be otherwise.) But Bloomberg would also enter Super Tuesday in a challenging position. And Buttigieg and Warren don’t have a lot of obvious strengths on Super Tuesday, either.

Of course, anything is possible. Sanders could win South Carolina on Saturday and then some scandal could emerge from out-of-the-blue on Sunday. But in all likelihood, Sanders winning South Carolina — one of more difficult states on the map for him — would put him well on his way to the nomination.





Confidence Interval: The Biden campaign is doing just fine