Bernie Sanders will probably win California on Super Tuesday. If none of his opponents drops out (or at least fade away) after South Carolina’s vote is counted on Saturday night, Sanders could easily earn two-thirds of California’s 415 pledged delegates, giving him a massive, and perhaps insurmountable early lead in the delegate race.

The key is the Democrats' 15% viability threshold. To win delegates from a state or a congressional district, a candidate needs to get at least 15% of the popular vote in that state or congressional district. Look at the RealClearPolitics polling average in California as of Saturday morning:

Sanders: 32.5%

Elizabeth Warren: 15.3%

Joe Biden: 12.5%

Michael Bloomberg: 10.8%

Pete Buttigieg: 9.5%

Amy Klobuchar: 5.3%

Tom Steyer: 3.3%

Tulsi Gabbard: 1.7%

Warren is the only Sanders challenger averaging above the viability line. In the latest CNN poll, only Sanders was above the 15% line. By FiveThirtyEight’s average, everyone but Sanders is below 15%.

So if the second-tier candidates were to split the vote too evenly, Sanders would be the only statewide viable candidate in California. That would mean even if he gets only 35% of the statewide vote, he would get all 144 statewide pledged delegates. (Technically, there are two categories of statewide pledged delegates, but that’s immaterial for this discussion.)

Most of California’s delegates are not awarded on the statewide level, but by congressional district. There is no way to estimate how those 53 districts will go, but it’s important to remember that the 15% viability threshold will apply on the congressional level as well.

Each district gives out four to seven delegates (with the more Democratic districts having more delegates). The viability threshold means those four to seven delegates will, in many districts, be divided two or three ways. And if a district happens to look exactly like the FiveThirtyEight average, where the second-place candidate finishes below 15%, then Sanders would get all the delegates in the district, even if he gets only 35% of the vote.

So in our hypothetical where he wins statewide with 35% and nobody else gets 15%, we can assume Sanders will be viable in every or almost every congressional district and that he’ll win at least half of the districts. The odds are against four or more candidates hitting the 15% threshold in most districts, and so wherever Sanders wins with 35% or more, he’ll get half the delegates or more. In some districts, he’ll get all the delegates, because he’ll be the only viable one.

Sanders’s best counties four years ago were small rural counties. He beat Hillary Clinton in the 1st Congressional District by 18 points. Assuming there's some brand loyalty there, it wouldn’t be hard for Sanders to get all four delegates there by being the only one above 15%.

Sanders could definitely get half of the 271 district-level delegates, which, combined with the 144 statewide delegates, could give him about 280 of California’s 415 pledged delegates. If the non-Sanders vote is more or less evenly split, and Warren is picking up a few congressional district delegates here, while Biden is picking up a few there, and Buttigieg is grabbing a few over there, there’s a decent chance the second-place finisher in California gets only 50-75 delegates.

In other words, California could give Sanders a net 200-delegate boost over whoever emerges as his closest rival. That would be very hard to make up, precisely because of this same system of proportional allocation.

Sanders will get delegates in every state after Super Tuesday, because he will easily get 15% in every state, particularly if other candidates drop out. So if my above scenario takes shape, Sanders might be able to build a plurality of delegates, or even a majority, without winning a single state after Super Tuesday.