Former Vice President Joe Biden beat Sen. Bernie Sanders handily in the 2020 Mississippi Democratic primary, continuing a sweep across the Southern states that has put him in the pole position for the party’s presidential nomination.

The win in Mississippi could portend a strong night for Biden on a pivotal day in the primary calendar, now that the race has been narrowed to the former vice president and Sanders following Super Tuesday. Biden looks well-positioned to build on his delegate lead against Sanders in the six states voting on Tuesday, which collectively will award 352 delegates to the Democratic National Convention.

And 36 of those delegates will be won in the Mississippi primary. Biden could conceivably enjoy a clean sweep: In the final tally, Sanders needs to clear 15 percent either statewide or in one of its four congressional districts to win any delegates. The early call for Biden suggests he won overwhelmingly, but we won’t know for sure how the delegates will be allocated until all the votes are counted.

Biden’s triumph in Mississippi is no surprise. The FiveThirtyEight weighted polling average in the state showed him with a nearly 50-point lead over Sanders, with former South Bend, Indiana, Mayor Pete Buttigieg and Sens. Amy Klobuchar and Elizabeth Warren out of the race. Biden has been winning black voters by huge margins across the South, and 84 percent of potential Democratic primary voters in Mississippi are black, according to FiveThirtyEight.

It was black voters who carried Biden to his critical victory in South Carolina last month, which revived his faltering campaign, and his big Super Tuesday when he won seven states across the South and surpassed Sanders in the delegate lead. Heading into Tuesday night, Biden had won 612 DNC delegates compared to Sanders’s 536 in the primary so far.

By the end of the campaign, a candidate needs to win 1,991 of the nearly 4,000 DNC delegates up for grabs in the primary elections and caucuses to clinch the nomination before this summer’s convention. Biden has overtaken Sanders, who briefly looked like the frontrunner after a strong start in the early states, as the candidate most likely to reach that threshold, according to the FiveThirtyEight primary forecast.

It would take another significant shake-up in the race for Sanders to overcome Biden’s apparent advantages. Biden is leading Sanders in national polling, and election experts think the states coming up on the calendar are more friendly to Biden than to Sanders. In Florida, which is worth 248 delegates, Biden commands a 37-point advantage in the latest FiveThirtyEight polling average. He also leads Sanders in Illinois (184 delegates) and Ohio (153 delegates), according to the polling. Polls are not infallible, but for now they uniformly suggest Biden is the frontrunner for the rest of the race.

The next big day in the primary schedule is Tuesday, March 17, when four states (Florida, Illinois, Ohio, and Arizona) worth a collective 577 delegates will vote.

By that point, more than 60 percent of the Democratic delegates will have been awarded, and whoever holds the lead will be the clear favorite to earn the party’s nomination and take on President Donald Trump in the November general election.