I don't think most governments in Europe could be considered "left" at all, especially not right now, but most European countries have a quite healthy and significant presence of left-wing parties in their parliaments anyway, while in the US Sanders is on the very extreme end of what Democrats (who can't really be described as left-wing on the whole) have to offer already.

That doesn't apply to every European country though. I live in Poland, where left-wing parties have struggled to enter the parliament for many years now and the main fight happens between liberal right and far right. The US scene, although different in several important aspects, appears somewhat similar in this regard. We also have some individuals in the major liberal right party that could transfer into a left-wing party without raising too many eyebrows.