Complex sentence: They would provide the means to deal effectively with provincial rebellions, and inevitably grant the national government greater sway over the provincial government, and in turn the party in power would gain greater ascendancy in national politics through patronage and office appointments.
Split into simpler sentences: They would provide the means to deal effectively with provincial rebellions and inevitably grant the national government greater sway over the provincial governments. In turn the party in power would gain greater ascendancy in national politics through patronage and office appointments.