Governments are formed when a group of people gathers together, either freely or by force, and lives together in a community with a shared set of laws. The government is the entity which creates and enforces the laws. What is the moral grounding of the government?
In the old days in Europe we had kings who ruled by divine right. In principle they could declare whatever law they liked. In practice they were hemmed in in various ways. These days the U.S. and Europe mostly have elections. The elected government can pass any law within certain limits, but the laws are subject to repeal by later governments installed by later elections. The court system is also able to rule that certain laws are inappropriate, based on arguments from a higher set of laws–in the U.S., the constitution.
In the last resort, governments enforce their laws by force. Therefore, we have to ask: what is the moral basis for their actions? In a democratic system in which the government is freely elected, the presumption is that the government acts morally because it derives its powers from the consent of the people who elect it. In a monarchy in which the ruler rules by divine right, the presumption is that the government acts morally because God appointed the ruler, and God is by definition the source of all morality.
These points of view are easy enough to understand within the system. But consider what they look like from outside. In particular, what if you live in another country, and you are being invaded by the one under discussion.
If you are being invaded by a monarchy, then perhaps the monarch believes in a false God. In that case, you need to fight back against the monarch, try to convince the people that he or she believes in a false God and encourage them to rebel, try to assassinate the monarch. There is no reason for any special animus against the people: they may be heretics, and you defend yourself against them, but they are not really the enemy.
Or suppose you are being invaded by a democracy (Thomas Friedman once argued that one democracy would never invade another, but that rule clearly fell by the wayside during the Balkan struggles in the 90s). Now you are being attacked by representatives of all the people in the invading country. Since the people provide the moral grounding for the government, they are all responsible. They are all the enemy.
This point of view naturally leads to the war of entire societies, and the targeting of what were once known as innocent civilians–a practice which began in earnest in World War II. This seems like an unfortunate consequence. But there is no way for us to have the right to change our government without taking on the moral responsibility for the actions of the government. It’s not enough to say “I voted for the other guy.” We are still part of the society, and we live by its rules.
In a democracy, we are truly our brother’s keeper, because we are in part responsible for his actions. That is a heavy load to carry.