05/19/1898
https://www.presidency.ucsb.edu...
"In view of the occupation of Santiago de Cuba by the forces of the United States, it is ordered that postal communication between the United States and that port, which has been suspended since the op..."
"As other portions of the enemy's territory come into the possession of the land and naval forces of the United States, postal communication may be opened under the same conditions."
"The Postmaster-General is charged with the execution of this order in co-operation with the military commander, to whom the Secretary of War will issue the necessary directions."
"The revenues derived from such service are to be applied to the expenses of conducting it, and the United States postage stamps are therefore to be used."