Complex sentence: The Cape Prime Minister John Molteno correctly warned that a lop-sided confederation would cause instability and resentment, and advised full union as a better model for Southern Africa--but only at a later date, once it was economically viable and tensions had died down.
Split into simpler sentences: The Cape Prime Minister John Molteno correctly warned that the imposition of a lop-sided confederation would cause instability and resentment. He advised full union as a better model for Southern Africa--but only at a later date, once it was economically viable and tensions had died down.