The War in the West became a titanic struggle between millions of men living in a line of trenches 600 miles long from the Channel to Switzerland. That line of trenches would hardly move throughout the whole War and would dictate the tactics of both sides. And the reason was the machine gun.
The Germans treated the machine gun as an infantry weapon, and equipped their infantry battalions with them, sometimes two guns per battalion. The British, French and Belgians regarded the machine gun more as a light artillery weapon and issued few to the infantry. The result was that the Germans possessed overwhelming fire-power well forward that gave them control of the battlefield. The Allies reacted by also adopting the tactics of using their machine guns with interlocking arcs of fire, well forward and from protected positions. The ground between the opposing armies became a No-Mans Land. Thus the War became a stalemate with the machine gun proving to be a defensive weapon neither side could defeat. Attempts to break the deadlock included poison gas and tanks.