I remember reading a sci-fi book when I was in high school (around 1994). It was in the school library, but I am not sure how old the book was, although it seems to me the cover was in fairly new condition. I have tried all my google fu to no avail so I am hoping someone here can remember.
It was set on a future earth. There was some kind of battle between the future earth government and some other human group. colonists maybe?
The main character was a general who had been cloned, but the clone had turned traitor and was fighting for the other side. So his side didn't trust him because if his clone had switched, he might too (I believe the clones started as identical personalities from the moment of clone).
They had a form of spaceship teleportation that involved what they called a "bounce pipe" the stresses of teleportation would cause a certain number of bounce pipes to break on a regular basis and a great deal of time was spent talking about and trying to make sure there was a steady supply of them.