They wrote in the old days that it is sweet and fitting to die for one’s country. But in modern war there is nothing sweet nor fitting in your dying. You will die like a dog for no good reason.

Ernest Hemingway (1899–1961) American writer
Essay (1935-09), “Notes on the Next War,” Esquire, Vol. 4, No. 3
    (Source)

See Horace (23 BC).