The US military is the 14th largest user of oil in the world. They use as much as Greece. How does one make a tank that gets one mile per gallon of gas eco-friendly and "green" as it goes about its function killing people?
Don't forget battlefield contamination from depleted uranium rounds, destroyed crops, buildings, vehicles, fuel spills into the local water system, medical waste in the local dump, and just plain litter from military bases and troops.
Conscience does not exist if not exercised
"No matter how cynical you get, it's impossible to keep up!