In the context of World War I, 'stalemate' refers to the impossibility of achieving decisive results through battlefield conflicts and clashes. Territory might be gained or regained; advances were sometimes made; small victories might be won. Yet, until late in the war, stalemate dominated the war's major fronts, with no significant or decisive results able to be won, no matter how much effort (or life) was expended.
Machine gun
the germans had alien technology
The United States entry into the war
The entry of the U.S. into the war.
Stalemate.
Would you mind reposting your question with a little more information? There was a stalemate in most of World War I, but World War II happened in so many places, that I do not know of the occurence in your question . . .
8 years
no one gains or looses ground
On a Coast Line somewhere
The stalemate generally refers to the Trench warfare in France 1915-1918.
the entry of the U.S. into the war.
They did help break the stalemate.