Biden won because he assembled a multiracial moderate coalition. For months, Democrats have pointed to South Carolina as the first test of the presidential field that truly reflects the influence of African-American voters, a critical part of the Democratic electorate. That was indeed a huge factor in Biden’s win: Blacks made up 57% of the electorate for Saturday’s primary, and Biden won a whopping 64% of their votes.

But Biden also struck a chord with white Democrats, who were 38% of the electorate. By a margin of 34% to 25%, Biden won the white vote over Bernie Sanders among an electorate whose political memories go back to party stalwarts such as Sen. Ernest Hollings, whom Biden eulogized on a trip to South Carolina last year. Theirs is a different type of centrism, but still strong in the state. And both the black and white Democrats who chose Biden were more moderate than the woke, progressive Democrats who powered Sanders to victory in Iowa and New Hampshire.

Nor is that centrism exclusive to South Carolina. The factors that led to Biden’s win here all apply to other states with similar mixes of black and white voters. Looking ahead to Super Tuesday, Biden appears strong in North Carolina and has a chance to finish well in Alabama, Arkansas, Oklahoma, Tennessee, and possibly even Texas. If, as expected, Sanders wins California and other non-Southern states, the results of this primary, combined with Super Tuesday, could set up a regional showdown for the Democratic nomination, with a deeply divided party struggling to settle on a nominee.