How we change what others think, feel, believe and do
The two sides face one another in effective impasse. Trenches are dug for shelter, allowing lateral movement of foot soldiers. They are deep enough to provide protection from snipers and explosions but also shallow enough to permit peering over the edge and scrambling out as required.
The distance between opposing trenches is determined by a complex mix of factors such as the ability to observe, attack and defend. Betwen the two sides is a 'no man's land' where mines, barbed wire and other dissuasions against a surprise attack may be pkaced.
At strategic moments, one side may go 'over the top' to charge the enemy lines in the hope of breaking through. Where this is successful, the enemy might then fall back to trenches further away.
A more extreme form of trench war may be found where underground tunnels are built, particularly to protect from aerial bombardment.
Trench war may be used when both sides have the symmetry of approximately equal force and in particular where the defense system of each is stronger than the attack force of the other.
The stalemate that this causes means that soldiers need semi-permanent shelter from opposing gunfire, particularly when they are in open countryside. These entrenched positions then become places of relative safety that, paradoxically, dissuade the soldiers from moving elsewhere.
Trench war becomes less effective when the trenches can be bombed or where other means allows forces to go around the trench system.
Trench war was particularly prevalent in the First World War in Europe where the recent invention of automatic weapons meant that an infantry charge could be mown down before it reached its target.
In an argument, dig in. Refuse to retreat. Snipe at the other person from a safe distance. Wear them down and then launch sudden attacks. If they repel your attack just return to your safe position.