From Death and Taxes:
The Guardian is reporting that, according to a dossier they obtained from an anonymous source within the Democratic Party, the Clinton campaign and others who do not want to see Sanders receive the nomination will be accusing him of “sympathizing with the USSR during the Cold War” and “associations with communism” in Cuba. That former allegation is apparently based on the fact that he went on a trip to the Soviet Union to visit a twinned city while mayor of Burlington. The latter is tied to other quotes cherry-picked from throughout the senator’s career about China and Nicaragua.
Seems like branding a candidate a “socialist” is just a tad too 2000-and-late for the Clinton camp (also, probably ineffective when both the candidate and a large portion of the Democratic voter base openly embrace the term) so Hill-Dawg decided to just go full McCarthy with some good ol’ fashioned Red Scare fear-mongering.