The speaker starts with a familiar piece of advice, "know your enemy," and then quietly turns it into a problem. Each question pushes the knowing a little deeper. First he imagines learning the enemy's language, then watching his television and reading his newspapers, then his poetry, and finally his mind, his hopes, his loves and his fears. The short, stacked lines feel like a man talking himself into a corner.
The turning point is the plain admission, "What if he's really like you or me?" Once the enemy has become a person, killing him is no longer easy. The last image is blunt and physical: the bayonet goes into the enemy's heart, yet the speaker feels his own blood running along the groove of the blade. The mood is uneasy and troubled. The poem suggests that understanding another human being makes violence against him feel like violence against yourself.