Former Vice President Joe Biden continues to hold a lead in South Carolina, but his advantage has narrowed sharply after months in which he was ahead of the other contenders by double digits. A CBS News poll released Sunday shows Biden has the support of 28 percent of likely democratic primary voters in South Carolina, with Sanders in second place with 23 percent. That is within the poll’s margin of error, which is plus or minus 5.5 percentage points. Businessman Tom Steyer has also made impressive gains in the state and is now in third place with 18 percent followed by Sen. Elizabeth Warren with 12 percent and Pete Buttigieg with 10 percent.

This latest poll was finished before Sanders’ commanding victory in Nevada. But still, the poll points to a much different race in the state than what it looked like only a few months ago, when Biden held a commanding 28-point lead. In early October, for example, Biden was at the top of the pack in South Carolina with 43 percent, followed by Warren with 18 percent and Sander, 16 percent. At the time, Steyer had a measly 2 percent.

The former vice president has long had a strong advantage in South Carolina largely thanks to his support among black voters. But since the fall Biden’s support among black voters has declined 19 points. In contrast, Steyer’s support among black voters has increased sharply.

Experts say that a Biden victory in South Carolina on Feb. 29 could revive his candidacy but another loss could end it. “Biden really has to stake his claim here,” said Bob Oldendick, a political science professor at the University of South Carolina. “I think he has to win. If he does not win in South Carolina, it’s pretty much the end of his campaign.”

Biden blamed Steyer’s big spending in South Carolina for his drop in support among black voters. “What’s happening is you have Steyer spending … millions of dollars out campaigning there, so I think a lot’s happening in terms of the amount of money being spent by billionaires to try to cut into the African-American vote,” Biden said on CBS’ Face the Nation. Regardless, he insisted that he continues to be confident he will come out on top in South Carolina. “I feel good about where we are. I feel good about going into South Carolina. And I feel good about the kind of support I’ve had with African-Americans around the country,” Biden said. On Saturday night, Biden claimed victory with a distant second place finish in the Nevada caucuses. “I know we don’t know the final results yet, but I feel really good,” Biden said. “You put me in a position. You know, the press is ready to declare people dead quickly but we’re alive and we’re coming back and we’re going to win.”

In new CBS News polling @JoeBiden is down 19% in South Carolina among black voters, standing at 35%. He suggests "billionaire" candidates are spending money "to try to cut into the African-American vote" ahead of the state's primary https://t.co/VA2Hoc5ej6 pic.twitter.com/hztPwlHiKI — Face The Nation (@FaceTheNation) February 23, 2020