I am looking around and 90% of what I find is just that it started in the civil war.

Were soldiers not allowed to vote when deployed before the civil war, was it just a logistical problem, or could they?
Then there is another act allowing voting in WWI, was the Civil War voting temporary?
Were overseas/deployed soldiers not allowed to vote (presumably in peacetime as they seem to pass temporary measures for various wars) until the 80s?
Were soldiers just stationed in a different state not allowed to vote at various times?
Could a lot of the military not vote in the beginning of the country due to not owning land?