

Bernie Sanders rallies with supporters at Wofford College in Spartanburg, S.C. (Jonathan Ernst/Reuters)

Graphics columnist

If you don’t understand the way that the Democratic Party splits its convention delegates, perhaps you are not a rocket scientist. But it might help to be one.

The big factors are all locked in fine print. One that matters? A rule that could help Sen. Bernie Sanders (I-Vt.) win big on Super Tuesday, all but assuring him the Democratic nomination.

To understand this rule, let’s use California as an example. The state will award 415 Democratic convention delegates on Super Tuesday. They will be distributed this way:

144 delegates will be are awarded proportionally according to statewide results. 271 delegates will be awarded proportionally according to the vote in each congressional district. Here are two examples: District 8 4 delegates District 12 San Francisco 7 delegates Source: California Democratic Party. 144 delegates will be are awarded proportionally according to statewide results. 271 delegates will be awarded proportionally according to the vote in each congressional district. Here are two examples: District 1 4 delegates District 12 San Francisco 7 delegates Source: California Democratic Party. 144 delegates will be are awarded proportionally according to statewide results. 271 delegates will be awarded proportionally according to the vote in each congressional district. Here are two examples: District 1 4 delegates District 12 San Francisco 7 delegates Source: California Democratic Party. 144 delegates will be are awarded proportionally according to statewide results. 271 delegates will be awarded proportionally according to the vote in each congressional district. Here are two examples: District 1 4 delegates District 12 San Francisco 7 delegates Source: California Democratic Party.

Now, the Big Catch: A candidate has to win at least 15 percent of the vote (state-wide, for state-level delegates, or district-wide, for district level-delegates) to win any delegates. If you get less than that in the popular vote, you get zero delegates.

Why is this good for Sanders? In many California polls, the senator is the only candidate consistently above that 15-percent threshold. Meaning there is a decent chance that Sanders could win most, if not all, of the 144 delegates awarded at the state level. This is how the leading candidates have been performing in polls of California voters, on average:

Only candidates with more than 15 percent of the vote win delegates. Sanders 30% 25 20 Warren 15% Biden Bloomberg 10 Buttigieg 5 0 Oct. Nov. Dec. JAN. FEB. Source: Post Opinions Simulator, as of Feb. 28. Only candidates with more than 15 percent of the vote win delegates. Sanders 30% 25 20 15% Warren Biden Bloomberg 10 Buttigieg 5 0 Oct. Nov. Dec. JAN. FEB. Source: Post Opinions Simulator, as of Feb. 28. California polling averages, as of Feb. 28. Sanders 30% Only candidates with more than 15 percent of the vote win delegates. 25 20 15% Warren Biden 10 Bloomberg Buttigieg 5 0 Oct. Nov. Dec. JAN. FEB. Source: Post Opinions Simulator.

Additionally, Sanders has a strong on-the-ground presence in California, with 20 offices around the state. That doesn’t mean he will win every district. But with so many other people in the race, Sanders is also in a good position to secure an outsize share of the district-level delegates.

That rule could also help Sanders do well Tuesday in other states — such as Massachusetts, North Carolina and Texas — although other candidates are also poised to get a piece of the prize in those states.

Here’s who has the edge in the Super Tuesday states with highest number of delegates, according to polling averages compiled by my colleague David Byler:

Texas, 228 delegates 30% 25 Sanders 20 Biden 15% Bloomberg Warren 10 Buttigieg 5 0 Nov. Dec. JAN. FEB. North Carolina, 110 delegates 35% 30 25 Sanders 20 Biden Bloomberg 15% Warren 10 Buttigieg 5 0 Nov. Dec. JAN. FEB. Massachusetts, 91 delegates 30% 25 Sanders 20 Warren 15% Buttigieg Bloomberg 10 Biden 5 0 Nov. Dec. JAN. FEB. Minnesota, 75 delegates 30% Klobuchar 25 Sanders 20 15% Warren 10 Biden 5 Buttigieg 0 Nov. Dec. JAN. FEB. Note: Virginia will award 99 delegates on Super Tuesday, but polls in the state are insufficient to draw trend lines. Source: Post Opinions Simulator, as of Feb. 28. Texas, 228 delegates 30% 25 Sanders 20 Biden 15% Bloomberg Warren 10 Buttigieg 5 0 Nov. Dec. JAN. FEB. North Carolina, 110 delegates 35% 30 25 Sanders 20 Biden Bloomberg 15% Warren 10 Buttigieg 5 0 Nov. Dec. JAN. FEB. Massachusetts, 91 delegates 30% 25 Sanders 20 Warren 15% Buttigieg Bloomberg 10 Biden 5 0 Nov. Dec. JAN. FEB. Minnesota, 75 delegates 30% Klobuchar 25 Sanders 20 15% Warren 10 Biden 5 Buttigieg 0 Nov. Dec. JAN. FEB. Note: Virginia will award 99 delegates on Super Tuesday, but polls in the state are insufficient to draw trend lines. Source: Post Opinions Simulator, as of Feb. 28. Texas, 228 delegates North Carolina, 110 delegates 30% 35% 30 25 Sanders 25 20 Sanders 20 Biden Biden 15% Bloomberg Bloomberg 15% Warren 10 Warren 10 Buttigieg Buttigieg 5 5 0 0 Nov. Dec. JAN. FEB. Nov. Dec. JAN. FEB. Massachusetts, 91 delegates Minnesota, 75 delegates 30% 30% Klobuchar 25 25 Sanders Sanders 20 20 Warren 15% 15% Buttigieg Warren Bloomberg 10 10 Biden Biden 5 5 Buttigieg 0 0 Nov. Dec. JAN. FEB. Nov. Dec. JAN. FEB. Note: Virginia will award 99 delegates on Super Tuesday, but polls in the state are insufficient to draw trend lines. Source: Post Opinions Simulator, as of Feb. 28.

There is always a chance that voters might change their minds between now and when they reach the voting booth.

But, at the moment, Sanders is in position to make significant delegate gains in every key state on Super Tuesday. Especially in California, the biggest prize of the day. And that simple rule could make all the difference.

Read more:

Bill Whalen: Californians finally get to play presidential kingmaker. Will they blow it?

Paul Waldman: Everyone calm down. There won’t be a brokered convention.

Marc A. Thiessen: Now Sanders wants a Green New Deal for the entire world

Michael Gerson: The false authenticity of Sanders and Trump

Fareed Zakaria: Bernie Sanders’s Scandinavian fantasy

Henry Olsen: Two reasons Bernie Sanders should terrify Democrats: Florida and Pennsylvania