 Complete the following phrase:  Based on the assumption that Kentucky neutrality would act as a shield against a direct invasion from the north, circumstances that no longer applied in September 1861, Tennessee initially had sent men to Virginia and concentrated defenses in the Mississippi Valley. Even before Johnston arrived in Tennessee, construction of two forts had been started to defend the Tennessee and the Cumberland rivers, which provided avenues into the State from the north. Both forts were located in Tennessee in order to respect Kentucky neutrality, but these were not in ideal locations. 