It was a mistake to let up on Biden on cutting Social Security before SC. Biden was always the real threat. Give an inch and they'll take a mile, unfortunately.

Several people from SC said that hitting Biden on SS would have been effective there, but the Bernie campaign didn't run any ads there on it.

By just running ads of Biden's own words on SS, SC could have been much closer. The campaign needs to be on its game more and use money more effectively.

Also, they need be savvier in dealing with the establishment. That tweet "Republican establishment, Democratic establishment. You can't stop us" may have raised red flags that Bernie would be hostile and wouldn't be willing to work with people when that's not Bernie's approach at all. Maybe that contributed to the sudden Stop Sanders pushback from the establishment. The establishment is not a monolith, some people may be sympathetic to Bernie, and tweets like that aren't useful in any way.