England hath need of thee: she is a fen Of stagnant waters (1-2)
This is pretty clear: any comparison to a swampland full of fetid, gross water is never a good thing. England is in a foul state of moral corruption, according to Wordsworth.
We are selfish men; Oh! Raise us up, return to us again; And give us manners, virtue, freedom, power. (6-8)
Hmm…very interesting. The fact that Wordsworth lumps "manners, virtue, freedom, and power" together indicates the relationship between morality and success – a healthy nation achieves things like "freedom and power" through being kind and virtuous.
Thy soul was like a Star, and dwelt apart (9)
…dwelt apart in a better place, that is. Milton's moral superiority set him apart from the rest of the flawed mass of humanity.