How do I get a dictatorship in HPM? Furthermore, how do I get more slaves?

Playing as Gran Columbia and trying to do a run where my country is a Slaver run dystopia. I have a small colony in Africa as well, and I see no option to restart the slave trade. I've played blood and iron, which usually has the reactionaries eventually coup the government given enough time, this has not happened yet. What am I missing?

(Disclaimer: I'm well aware industrialization is just better, but I'm past the point of just playing to become the dominant power, I play for the fun of it. I feel the need to add this knowing that at least one person is going to reply with "abolish it")