If you seriously think that the US Democratic party, as compared to leftist parties in Europe, is closer to Walden Pond than the Atlantic Ocean in terms of leftism, then you and I clearly live on different planets and we don't have enough common ground to have a useful discussion.

In fact, historically speaking, even the US Republican party today is closer to the Atlantic Ocean than Walden Pond in terms of leftism. What today's US Republicans consider "conservative" would have been considered so far left as to be radical to the US Republicans of the late 19th century.