Joe Biden called on Bernie Sanders to accept greater accountability for the words and actions of his supporters after what the former vice president called the “outrageous” threats on a prominent union that criticized the Vermont senator's health care plan.In an exclusive interview airing Sunday on NBC’s “Meet The Press,” Biden said the Vermont senator “may not be responsible for it, but he has some accountability.” The powerful Culinary Workers Union said this week that Sander's backers had “viciously attacked” its members after the labor group warned about the Medicare for All proposal.Read more on this story at NBCNews.com and watch "Meet the Press with Chuck Todd" tomorrow at 9 a.m. ET or check local listings.