Voting in the Democratic Primary is underway. Delegates have been allocated. We are not choosing a nominee in the South Carolina Democratic Primary — or any of the other upcoming state contests — from scratch now. We are voting in the context of votes that have already been cast.

This contest is a delegate-counting exercise. There are a limited number of delegates. They are apportioned based on a state’s primary/caucus results. A candidate needs 1,991 delegates to secure the Democratic nomination on the first ballot at the national convention. Failure to meet that delegate threshold in the primary voting process will result in a so-called “brokered convention.” This means that Democratic delegates choose the party’s nominee at the national convention this summer.

Right now the delegate tally is as follows:

Buttigieg 23
Sanders 21
Warren 8
Klobuchar 7
Biden 6

A poll came out today showing Bernie Sanders winning California by 18 points. I can’t do the precise delegate projections from that poll, but I am confident that a big win in CA alone will make it virtually impossible for any other Democrat to catch up to Bernie in the delegate race — certainly not when there are still six more people in the field siphoning off more than half of the delegates.

I’m anxious to see what happens in NV. But as the field stands currently, Pete Buttigieg is the only contender with a legitimate case for prevailing as the A.B.B. (anybody but Bernie) candidate on the basis of delegate math.

So while you’re excited that [your non-Bernie candidate] did well tonight in the debate, realize that we’ve got an extremely narrow window in which to consolidate the A.B.B. field.

It’s already highly unlikely anybody can surpass Bernie in the delegate count if we stay on the current trajectory. It’s also highly unlikely that the current trajectory changes much. Bernie with his diehard supporters will continue winning the plurality of votes while everyone else scraps for the rest. That part is exactly what we watched Republicans do in 2016. Who comes in second may change, but not enough to matter in the delegate race. The contest results almost certainly won’t turn upside-down at this point. Barring some huge unforeseen circumstance, upcoming elections will shake out largely how we expect.

Unless the field narrows drastically and fast, we will arrive at the national convention with no candidate having secured the requisite 1,991 delegates to lock up the nomination on the first ballot. Bernie will hold first place in the delegate race, all hell will break loose, and we will probably nominate him because he won the most votes and earned the most delegates. (If we don’t nominate him, the Bernie Bros burn the place down. Actually, they may do that anyway.) Then we will go on to lose the general election to Donald Trump.* The End.

*Edit: I am not suggesting that nominating Bernie Sanders is the reason we lose. We lose because it’s an uphill battle to unseat a sitting president, especially when the economy is doing well by most measures. Still, in my opinion, nominating Sanders will preclude Democrats from overcoming the already-tough odds we face. Additionally, it’ll hurt down-ballot Democrats in places like South Carolina.