Round 4, South Carolina

Round 4 in the Democratic nomination battle.

In the first three rounds, the story has been Sanders.

By the numbers:

Iowa Caucus (the procedure adjusts for the voters second choice candidates)
Sanders won with 24.7% in the first round
But when adjusted for the caucus procedures Buttigieg got a slim delegate lead (13 vs. 12) because caucus takes into account voter's second choice candidates.

New Hampshire (straight up primary so one vote for one candidate)
Sanders won with 25.7% just beating out Buttigieg

Nevada Caucus (the procedure adjusts for the voters second choice candidates)
Sanders won with 34% and when adjusted for the caucus procedures he won easily (24 delegates to Biden’s 9).

South Carolina is up next and a primary state (straight up primary so one vote for one candidate)
Key questions: 
Will Biden win and by how much if he does? 
I think Biden needs a pretty large win to right the ship.
A +10% points would solidify his claim to be the comeback kid!
Clearing 40% would be even better
UPDATE: Biden cleared 40% with 48.4% and won by almost 30%

How many percent will Sanders get?
Sanders has a hard-core base of support that is around 25-30%. In 2016, he had his hard-core supporters AND the anybody but Clinton voter thus the reason for the hotly contested 2016 nomination race. Nevada was the first indication this season that maybe he is starting to break beyond his core voters. South Carolina will be another test. 
If his numbers drop back to Iowa and New Hampshire levels then he may really have a glass ceiling of support. 
UPDATE: Sanders came in at 19.9% the lowest of the first four races. IN states not known for left politics, Sanders appears to have a glass ceiling.

Will South Carolina voters decide it is a two-person race? 
If the third-place finisher is around 10% or less that means people are abandoning the lower tier candidates. Biden has the name ID and Sanders has the cash to compete widely in Super Tuesday. However, Buttigieg/Warren/Klobuchar are running out of money and won’t be able to run nation-wide in super Tuesday so they need to have a strong third and weaker than expected Biden/Sanders numbers in order to really remain viable. Steyer and Bloomberg are billionaires so they can stay as long as they want. But at some point they are businessmen and will eventually get out when they feel they have satisfied their egos enough.
UPDATE: Steyer came in at 11.3%, Buttigieg 8.2%, and Klobuchar 3.1% and all three have suspended their campaigns.