Republican Senator Tim Scott of South Carolina believes that among the field of Democratic presidential hopefuls, Vermont Senator Bernie Sanders is the one who poses the "biggest threat" to President Trump in November.

"Bernie Sanders brings that outside game in a similar fashion that President Trump did in 2016," Scott said in an exclusive interview with "CBS This Morning" in Charleston, the site of Tuesday's Democratic debate, co-hosted by CBS News. "Think about the similarities. In 2016, Republican leadership, Republican wisdom said that there is no way in the world out of the 17 candidates, Donald Trump will be the president. I think it's very similar."

While Scott said that Sanders is the Democrat who brings the most significant challenge to Mr. Trump among the eight candidates still seeking the party's nomination, Mr. Trump is also a threat to himself.

"If he's on his game as he was at the State of the Union, I don't think there is a candidate in the country that can beat him," the South Carolina senator said. "If there is a second choice other than himself, it would be Bernie Sanders."

Sanders has emerged as the front-runner in the field of contenders seeking the Democratic nomination following his win in Saturday's Nevada caucuses. The victory builds on his momentum ahead of the primary in South Carolina on Saturday and Super Tuesday on March 3.

Scott said Sanders has succeeded in drawing support from voters because of his focus on health care, which is an important issue for African Americans in particular. Sanders's signature health care proposal is Medicare for All.

"Bernie Sanders is doing something in 2020 that he could not do in 2016, which is getting African Americans and Hispanic voters to take a second look at his campaign," he said. "I think perhaps a primary reason is health care. If you look at what stands out the most in his campaign is he is undeniable a socialist, but he is strong and clear and competent on the issues he supports and the issue of health care is a big issue in the African-American community and I think it is the issue for why he ended up with 51% of the Hispanic vote in Nevada."

While Scott said Sanders could be a danger to Mr. Trump's political future, the senator said former New York City Mayor Michael Bloomberg would be the easiest Democrat for the president to beat in November.

"Mike Bloomberg has been so provocative. He has so many challenging story headlines," Scott said. "The narratives for as President Trump calls him 'Little Mike' would be easy for President Trump to take strong advantage."

Sanders will be on stage in Charleston for Tuesday's debate, which is the last before Saturday's primary and gets underway at 8 p.m. ET. Joining him are Joe Biden, Bloomberg, Pete Buttigieg, Amy Klobuchar, Tom Steyer and Elizabeth Warren.