In 1861, Lincoln called for volunteers as the war broke out. The roles that women could play were relatively limited. Emma didn't let that stop her. She posed as a man and eventually risked her life multiple times as a spy behind rebel lines (eleven times to be exact!).
What motivated Edmonds to take such risks? She wrote a memoir (entitled, Nurse and Spy in the Union Army) shortly after the war ended. On the first page she answered that question:
It was not my intention, or desire, to seek my own personal ease and comfort while so much sorrow and distress filled the land. But the great question to be decided was, what can I do? What part can I myself play in this great drama?There is a greater war and a greater drama. And there is a greater sorrow and and a greater distress. What questions are we asking? And what are we deciding?