How did the civil service help to maintain the stability of the Roman Empire?

Although the senate still functioned, civil servants drawn from plebeians and even former slaves actually administered the empire. Even after Augustus' death, the empire maintained stability because of the system of government he had established. The senate appointed him dictator for life.

b. sec, foreign relations

basic principles: federalism, separation of powers, checks and balances, judicial review, representative democracy, limited government, rule of law, individual rights and responsibilities, consent of the governed, majority rule, popular sovereignty, equal protection.