What right did they have to have a military base in another countries territory, none at all is the answer, by that logic Britain should of kept a military base after the revolutionary war on American soil...
I latched onto this bit, just to prove how wrong and misinformed you are. By your statement, you are saying that Ft. Sumter and all the other Union forts were built in the Confederacy AFTER they seceded. http://en.wikipedia.org/wiki/Fort_Sumter
To sum it up: Fort Sumter was built following the War of 1812, as one of a series of fortifications on the southern U.S. coast. Construction began in 1827, and the structure was still unfinished in 1861, when the Civil War began.
I never claimed they were built after, I claimed they instigated the war by refusing to leave what was now property of the Confederacy, the fort belonged to the Confederacy, not the Union, the Union refused to leave it.