Joe Biden is still the front runner for the moment. If he wins big in SC, we will see Sanders fade fast. Sanders needs to over perform in SC, or the media will call the win an inflection point, the comeback kid, and all that stuff. Biden could then dominate following Super Tuesday. Then off to the Convention to see Bernie take his medicine once again.
Currently Sanders is the front runner, not Biden.
Biden is most definitely the front runner. All he has to do is win South Carolina big, and he will ride on to the nomination. If Biden wins big tonight, it is over for Sanders. Bernie needs a very strong performance tonight, or he is right back where he was in 2016.