Just going to say, niam, that if you really do think Sanders' continued presence on the political stage and his popularity is a detriment to the Democratic Party, I encourage you to support
Folasade Adeluola, his opponent in Vermont's Democratic Senate primary this August. While he might still run as an Independent even if he loses that primary, it would put him in a three-way race, which he would be more likely to lose, and should Ms. Adeluola defeat him (or even get a significant percentage of the vote) in the Democratic primary, it would send a message that he is not as popular among Vermont Democrats as he or anyone else would have us believe.
That said, I find it unlikely that he would lose, either in that primary or even in a three-way general election race, since he is consistently voted the most popular Senator when residents of the various states are polled concerning their Senators (and Sen. Leahy is almost always in the top ten), but if you really feel he should be repudiated by Vermont Democrats and, if possible, removed from the Senate, I would encourage you to support Ms. Adeluola's candidacy.
EDIT:
https://www.youtube.com/watch?v=6cSau9Nu_twVulnerable Republican House incumbents (such as in California, where there are seven House districts with a Republican representative that were won by Hillary Clinton in 2016) are attacking their Democratic opponents for supporting "socialized health care".