I'm writing about the antebellum south. So, yes, there is a whole "can of worms" as far as themes go. It's almost bottomless, the tangle of themes. But I didn't want "slavery is bad" to be the primary theme, or at least not the only one. Not because it isn't true--it is--but because it's obvious to our modern sensibilities. Of course, that isn't to say there aren't echoes of the old sensibilities in the twenty-first century. But it always seems to underplay the complexity of reality to focus on that one theme. Like I said, it's a tangled web, with other moral threads weaving in and out of the ugliness of slavery.
So one of my goals on this rewrite has been balancing the themes. I have at least two major thematic threads in this WIP ("Channing"). There's the thread regarding slavery (y'all, it's bad). There is also Caroline's slow emergence from self-abnegation after a moment of exploitation--it's the story of her losing her identity (and sense of agency) and then finding it again. And it's wrapped up with the issue of slavery, which is wrapped up with her husband, the one who exploited her. The trick is to not lean too heavily on one or the other and leave the other languishing for a scene--a chapter--two chapters. I don't want it to seem like the characters have forgotten about a thematic thread in their lives while something happens with the other. It's wrapped up with character as well, obviously.
I'm not much of one for moral nuggets--for moralistic nuggets. But I was pleased with the following passage, and I thought it summed up something important, bringing Caroline's theme to its end. Now, I've edited it a bit for the sake of spoilers, but here it is:
There were different kinds of inheritances. Money was useful—vital, in fact. But what was more vital—what was the very stuff of life—was love, real love. Not the sort that Harry practiced, but the sort that was open and warm and had a sense of humor to it. The question was not whether she would give up her son’s financial future for her own selfish desires; it was whether she meant to provide him a life in which he could come to a full understanding of love. And she would give up anything—anything—for that.