A new Fox News poll from South Carolina finds former Vice President Joe Biden leading among Democratic primary voters with 35%. Vermont Sen. Bernie Sanders is in a distant second place with 14%, and Sen. Kamala Harris is near him at 12%. No other candidate reaches double digits.

This is the first 2020 Democratic primary poll from South Carolina that meets CNN standards, though Biden has held large leads in other polls from the Palmetto State

After getting attacked by Harris during the first Democratic debates over a number of racial issues (including busing), there was a real question as to whether Biden would be able to hold onto African American support.

South Carolina, of course, is the first real test of black support in the Democratic primary. It's the fourth contest of the primary season, and a majority of Democratic primary voters in the state are likely going to be African American.

The Fox News poll indicates that Biden still holds a significant lead among black voters. It's not just that Biden leads the South Carolina primary. It's that his black voter support is even higher than his overall support. Biden leads among black voters in the Palmetto State with 41%, while he's only at 25% among white voters.

But while the poll was good news for Biden, it was bad news for Harris. Despite all the press surrounding Harris' debate moment, she actually came in third among black voters (12%) behind Biden and Sanders (15%). Beyond South Carolina, other polling suggests that Harris still has work to do with black voters.

CNN/SSRS, Harris is still about 20 points behind Biden among black voters overall. In an average of four live interview national polls ( ABC News/Washington Post NBC News/Wall Street Journal and Quinnipiac University ) taken after the debate, Biden holds 39% of the black vote. Harris is in second place with 20%, which is only 5 points ahead of Sanders' 15%. When you average these four national polls and the Fox News South Carolina poll (which has the largest black voter sample size), Biden's lead over Harris ups slightly, 39% to 18%.

Put another way: Biden's campaign is still largely being powered by black voters in a way Harris' campaign isn't. In the aforementioned same national polls, Biden does 17 points better among black voters than among white voters. That's very different than Harris, who does only 4 points better among black voters than white voters.

It would be easy to say Biden's black voter base exists merely because he was Barack Obama's vice president. That certainly helps, but there's probably more to it than that. Biden's more moderate ideology compared to other leading Democratic presidential contenders gives him an edge with black voters, who are some of the most conservative voters in the Democratic coalition. He also does best with non-college graduates ; more black voters than white voters lack a college degree

Now, it's not all good news for Biden. Biden's black voter advantage has shrunk compared to what it was before the first debate, down about 10 points compared to where he was in the spring. Harris, meanwhile, is up about the same amount (a little more than 10 points) with African Americans.

The question for Biden's campaign is whether his recent black voter slippage is a molehill or the beginning of something more. If it is the former, it's not a big deal. If it is the latter, Biden's campaign is in major trouble.

If someone like Harris continues to impress those being introduced to her, like she did in the first debate, Biden's lead with black voters may not last.