A hybrid-electric propulsion system includes a propulsor, a turbomachine, and an electrical system, the electrical system including an electric machine coupled to the turbomachine. A method for operating the propulsion system includes operating, by one or more computing devices, the turbomachine in a steady-state flight operating condition, the turbomachine rotating the propulsor when operated in the steady-state flight operating condition; receiving, by the one or more computing devices, a command to accelerate the turbomachine while operating the turbomachine in the steady-state flight operating condition; and providing, by the one or more computing devices, electrical power to the electric machine to add power to the turbomachine, the propulsor, or both in response to the received command to accelerate the turbomachine.