The guiding concern of just war theory is that it is wrong to harm people, therefore it is wrong to harm people en masse, as we do in war. Thus, just war theory stems from the observation that aggression of all kinds requires justification, and the theory attempts to lay out the justification for acts of war. War is aggressive, and it harms and kills individuals as well as damages nations, and therefore we should take seriously the moral weight of the obligations to avoid it. The two principle realms that just war theory addresses are jus ad bellum (justified principles for entering war) and jus in bello (justified principles of conduct within war).
American forces have come under scrutiny after an airstrike against Taliban forces in the Afghan city of Kunduz accidentally hit a Doctors Without Borders hospital. Doctors Without Borders (Médecins Sans Frontières) is a humanitarian organization founded in France on December 22, 1971. Their mission is to provide medical care to people in need, based on the belief that “all people have the right to medical care regardless of gender, race, religion, creed, or political affiliation, and that the needs of these people outweigh respect for national boundaries.” It is not uncommon to see the group provide aid to dangerous places like refugee camps, areas affected by natural disasters, sites of disease outbreak, and war zones.