2 JULY 2014

DOCID: 4130856to take appropriate actions.(U) History Today - 02 July 2014Run Date: 07/02/2014Throughout the early summer of 1863, UnionArmy and Navy units under MG UlyssesGrant and Admiral David Porter laid siege toVicksburg, one of the last Confederatestrongholds on the Mississippi River.During the siege, the Confederates hadinsight into Union movements because theywere copying Union flag signals and solvingthe cipher system that protected messages.All too often, however, the inside knowledgeh...