Despite the belief that the war would be over quickly, why did a stalemate occur along the Western Front?

Answer;

The trench warfare made it difficult for either side to win at advantage

Explanation;

A stalemate developed on the Western Front for four main reasons, one being that the Schlieffen plan failed, another reason was that the French were unable to defeat the Germans completely at the Battle of the Marne, another reasons was the "race to the Channel" and the last reason was that defending positions was far easier than attacking.

The Schlieffen Plan failed for a number of reasons, one being that Moltke, the German commander, had altered the balance of the forces so that the right wing had only three times as many troops as the left wing and since the right wing was smaller it advanced more slowly than had been planned.

There are many reasons for the stalemate develop along the western front, they are:

1. The Schlieffen Plan failed, the German commander made an alteration of the forced and made the right wing smaller than the left wing, this made it slower than planned and gave the opportunity to British and French forces to counter-attack. Also, the Germans didn't plan that Belgium would resist.

2. The second reason is that the Germans didn't imagine the Russians would attack them in the east, this is one of the reasons the right wing on number 1 was weakened.

3. Even though the Germans were completely exhausted they marched until Paris and French army was unable to defeat the German army at the Battle of Marne because they were in a large number and British and French army weren't as prepared as the German's.

4. After this both armies marched to the Belgian coast and stayed there for the next 4 years, this happened for many reasons such as bad weather - it was winter and there was a lot of mud - and the new advanced mechanizes weapons like machine guns made them stay inside their trenches to avoid more deaths.