Which lines in this excerpt from W.B. Yeats's "An Irish Airman Foresees His Death" suggest that the speaker voluntarily chose to take part in the war?
[I know that I shall meet my fate]
[Somewhere among the clouds above;]
[Those that I fight I do not hate,
Those that I guard I do not love;]
My country is Kiltartan Cross,
My countrymen Kiltartan's poor,
[No likely end could bring them loss
Or leave them happier than before.]
[Nor law, nor duty bade me fight,
Nor public men, nor cheering crowds,]