Paths of Glory by Humphrey Cobb

"Paths of Glory", written in 1935, takes place in the French army during World War I. An exhausted regiment is charged with the task of seizing an impregnable German stronghold. The mission fails, with fifty percent casualties, enraging the egomaniac general who promised victory to his superiors; three soldiers, as division representatives, are subsequently court-martialled and executed for "cowardice".