Personally I think the democratic party needs to fail before any sort of progressive party, let alone leftist party can form. They have shown that they won't stop reaching right so I basically look at this as a long or short term benefit choice.

Also in regards to

Yes, having everyone vote for the lesser evil would improve conditions somewhat, but that is idealistic wishing.

While a little nitpicky, I think it is important to make the distinction that the Democrats have never shown any interest in improving conditions and will only (slightly) slow their decay. They will never deliver on the sort of change that is large enough to be meaningful