When the power of Black voters' ballots were put to the test in the first primary in a majority Black electorate, former Vice President Joe Biden won the South Carolina primary on Saturday (February 29) with 48.4 percent of the vote, followed by Senator Bernie Sanders with 19.9 percent of the vote and businessman Tom Steyer with 11.3 percent of the vote. At publish time, 85 percent of South Carolina precincts were reporting.

"Thank you, South Carolina!" Biden tweeted. "To all those who have been knocked down, counted out, and left behind — this is your campaign. Together, we will win this nomination and beat Donald Trump."

This is a huge moment for Biden because South Carolina has a nearly perfect track record of picking the eventual Democratic Party nominee. (The only exception was the 2004 presidential race in which then-Sen. John Edwards took home a win but ultimately lost the nomination to then-Sen. John Kerry.) The former Vice President also needed the win, after Sanders swept Iowa, New Hampshire, and Nevada.

Turnout in the primary was primarily reliant on Black voters, who comprised 57 percent of turnout; 64 percent of those voters indicated they supported Biden, per Washington Post's exit polls. He also earned a plurality of white voters' support. But while Sanders once again earned the most support of voters aged 17–29, they only comprised 11 percent of the turnout on Saturday.

Out of the state's 63 delegates, 54 of them are pledged delegates, meaning they have to support a certain candidate depending on how the vote rolls out in that state; nine of them are superdelegates who do not have to commit to a specific candidate. Joe Biden earned 36 of the pledged delegates, and Sanders earned 11. In combination with the delegates he earned in New Hampshire, Nevada, and Iowa, Sanders is currently leading in pledged delegates with 57 total. Biden has 51 and Buttigieg has 36. But that's all set to change when, on Tuesday (March 3), voters in 14 states will cast their primary ballots, thereby assigning a host of new pledged delegates to candidates. It takes 1,991 delegates to win the Democratic nomination.

Steyer announced he was suspending his campaign later that night — but he promised to keep fighting for Americans, especially in South Carolina.

This is a developing story. MTV News will update it as we know more.