A Stalemate occurs when neither side can win quickly with an outright victory. This is what happened in WW1 between the Allied forces and the Germans for several reasons. One of which was on account of the failure of the Schlieffen plan which was a German movement to take over Paris, however the BEF caught up to them in Belgium and therefore the movement became bogged down and was forced to become trench warfare. The Germans had underestimated the power and strength or the BEF at Mons and Le Cateau and this miscalculation had cost them. The Schlieffen plan was only put into motion when it was certain the Russians would not be ready in time; however they were able to mobilize far quicker than expected so Germans were sent to the eastern fronts.
When the Allies retreated to the Marne, the Germans would have to retreat too, back to Aisne. They both decided then to dig trenches. In Belgium however, the terrain was flooded causing the big guns great difficulty due to vast amount of mud so everything was resorted to being pulled along by horses. This was a great issue in the ‘ race to the sea’ as everything had been totally dependent on speed, so too was the problem that they couldn’t go though Belgium as it was ‘ neutral’ territory. There was also a stalemate in the politics of the war, because if the Allied forces left the Germans to do what they wanted Germany could have taken over France with ease giving them a stronger position to invade Britain.
The Germans were stuck; they were in France and could simply claim the land they had previously obtained with the Allies having the only job to push them back out of there. But the Germans couldn’t go back and give up as their regime would have fallen into revolution. They did however still believe that if they killed enough allied soldiers they could win the war so they decided to stay put and test the BEF’s strength. Additionally when the war started everyone believed that the war would be over by Christmas that year so they exhausted themselves, by digging trenches it gave them all a place to rest and hide from the gradual wearing down of the other side by open warfare. In Conclusion, I believe the principle reason a stalemate developed on the western front is due to the failure of the Schlieffen plan and the chain of events it produced, for example the BEF landing and defending as the defensive was much stronger than the offensive which led to nothing also leading in the lack of German troops as some were sent to Russia. It was however the first time they had used trench warfare so time was needed in order to come up with tactics and strategies in order to win the war.