It is a commonplace that in modern wars - and that means virtually all wars since 1918 - the ratio of civilian to military deaths and injuries is not only greater than 1:1 but often many times greater. I know of only one exception, the Falklands War.
This commonplace ought to make any decent government wary of deploying its military in large-scale offensive operations. It is the young and the old, mothers and children who will die or be maimed for life. And because of the global hegemony of the United States, such tragedies will nearly all occur on one side only: in Vietnam, in Iraq, in Afghanistan it will be poor people who die. So dirt poor that they won't even have been able to blog that they see death coming.
Modern military technology is more powerful than the intelligence of those who wield it. That is why soldiers die in "friendly fire" incidents. It is also why it is hazardous to attend a wedding in Afghanistan. Intelligence may say it is a terrorist get-together and only when the body count is done can it be seen that it wasn't. And despite the relatively low risks they face, modern soldiers - conscript or volunteer - get jumpy and get high. They release tension with their guns or their missiles and then there are many dead.
A war may not in a particular case constitute what international law defines as a "crime of aggression", but even in that case it cannot escape the force of such truths.
Any politician who presses the case for war should be reminded that, with no ifs or buts, he or she is signing the death certificate of people - perhaps or probably many thousands of people - who have done no harm and intend no harm and including, most likely, many who are not old enough to have even heard the name "Tony Blair".