The Abrams tanks are renowned as " hard-to-kill" battle machines due to their sophisticated composite armor, which provides formidable resistance against hostile fire.
They are also narrowly trained for specific applications and thus fail badly when outside the limits of that training or in response to " spoofing" by adversaries.
One reduced the number of missiles used to shoot down enemy nuclear weapons. It also banned the testing and deployment of long-distance missiles for five years.