I always think they each took something from Heinlein - Pournelle got his politics, his passion, and worldbuilding, while Niven got his brainstorming and whimsy

I always think they each took something from Heinlein - Pournelle got his politics, his passion, and worldbuilding, while Niven got his brainstorming and whimsy. Put them together and you get a whole Heinlein.