The word "lest" is meant to come after something else. It means "for fear that" or "or else" or something similar. So it's not clear what you're trying to say. I don't know what "very systems" built by "the most evil" you mean either. Is it supposed to be obvious what you're referring to?
I clicked the link and remain confused. The poem does have in common the term "lest we forget", but apparently nothing else. It's also used in a grammatically correct way in the poem, but not in your post, since it's not following anything.
Power is not a meagre result. For those people who live by it, it is the ultimate goal, and they will use any means to obtain and expand it, no matter the cost to others.
That's a lot of work, a lot of malice, a lot of hate, from a lot of people, for a very meagre result.
If that's how you view your government you must live a really painful existence