I have great respect for Gysi, and always did since I first listened to a campaign speech from him in the mid-90s. He's a politician who has stuck to his principles and prevailed through adversities where many other people would have just given up. But, even if you disregard his flaws, blind spots around Russia, and the poor handling of the internal crises which have now led to a split of his party, he has hardly ever been in a position where he could truly make a change in politics. His party may have been part of the government in some German states, but he himself never has been. And this may sound cynical, but it's relatively easy to be a principled politician when there's not much at stake. It's when you actually have some power and influence, that the wheat separates from the chaff - when you actually have to handle all kinds of pressure from all sides and see what your principles are worth to you.

This is not a defense of any other politicians - I wish there were way more who didn't give up their principles at the first sign of pressure. I'm just saying that Gysi has rarely been in a position where he had to do that.

I am unfamiliar with the other two, but I would say similar concerns may apply there.