The speaker is someone who has seen too much and can't look away. Right from the first line, "I have seen the ruin of the nation," the tone is flat and certain, as if this is a report rather than a guess. What follows is less about politics than about how that knowledge feels in the body. Words grow "like fur on my heart," a strange image that suggests something warm and animal, but also something unwanted, a covering that thickens whether the speaker likes it or not.
The speaker is tired. "I am weary of seeing foul weather / coming upon us" makes disaster sound like a storm that keeps arriving, and the line "it is not a philosophical matter" cuts off any urge to treat this as an abstract debate. For the speaker, it is real and close. The closing image, night raving "like the sea / against a sunk ship," is bleak: the damage is already done, and what remains is darkness pounding at the wreck. The mood is heavy, resigned, and quietly urgent.