Feel like Bernie would be able to rally support in the rust belt a lot better than Scott could... his entire anti-outsourcing rhetoric would resonate extremely well there since that's where people were hardest hit. That same rhetoric may have won Trump the election there as well, so why not Bernie?
Tim Scott is a minority Republican, and Bernie Sanders didn't perform very well with minorities, so I think its possible Tim Scott could cut into typically Democratic minorities. Not enough to completely flip the vote, but enough to make a major difference.
