Consider war as armed conflict carried out collectively by a political entity, with deadly force and deaths of others envisioned.

Warring emerged with the development of agriculture and resulting inequality some ten thousand years ago and has been common since, including more recently linked to fossil fuels and other resources.

By contrast forager hunter societies had an equity ethic, and carried out vigilant sharing and had egalitarian sanctions using ridicule, ostracism and, if necessary, execution in order for the group to survive. Existing fights were mostly not conflicts among different groups but typically about personal issues such as jealousy within them. This was the original leisure time society and poverty as we see it today was absent.

Human health declined with the progress of agriculture.

The ability to produce and store food led to inequality as some had more than others and that led to conflict. One day, someone with power advantage said I am your lord, you must grow food for me, build me a castle in which to store my food and go to war to protect me and my food. This was the birth of feudalism.

There followed increased population density and segmented/hierarchical societies which led to conflict among different classes as the poorer ones sometimes wanted to rise up against the rich who acted to suppress them but who may have provided some sort of protection from other violence. Examples abound, but more recent ones even include slave societies. Two centuries ago Haiti became the only successful slave rebellion as it became an independent nation from its French rulers. This threatened the leaders of other slave societies. The lesson learned was that slaves should not represent an overwhelmingly large proportion of the population or they would organize and overthrow their masters.

Warring was also a large part of colonization with Europeans perhaps the most devastating as indigenous populations were destroyed wherever they went.

The most common wars are civil, namely those within countries. They are typically fought for control of government or resources and fueled by the availability of arms and intragroup animosity. Most such wars do not command much media attention with the current exception of Israel’s genocide in Gaza and the West Bank.

Hobbes writing Leviathan in 1651 stated: “I show in the first place that the state of men without civil society … is nothing but a war of all against all; and that in that war, all have a right to all things.” He pointed out that “life is nasty, brutish and short.”

War produces massive casualties with the first casualty being truth, making it difficult to discern what is going on.

There are multiple causes of wars. Inequalities of one kind or another, are the most important. Competition for resources (food, oil, land and people) have figured predominantly. Then revolutionary wars over ideology such as in Russia in 1917 and China in 1949. A recent category invoked in the United Sates are defensive or preemptive wars, now illegal under international convention.

Warring tries to protect economic interests, usually of the rich, as part of the pursuit of power with nationalism figuring prominently. Religious wars feature prominently too in the Bible, medieval Europe and in other faiths. Forced migration leads to conflicts of many kinds. Advancing capitalism and democracy is a stated reason for America’s many war efforts. The U.S. has been at war in one form or another in almost every year since its founding in 1776. This includes active military engagements such as foreign wars, regional conflicts or conflicts with native Americans. Consider war as a part of the American ethos.

All American wars since WWII have not been officially declared and the U.S. has not done well. The U.S. lost in Korea (or fought to stalemate with N & S Korea created). Then the Vietnam war (or as the Vietnamese call it, the American War), began to prevent communist North Vietnam rule, and resulted in victorious rule by communist North Vietnam. The United States entered Afghanistan to fight the Taliban in supposed retaliation for the 9/11 attack on New York City, but after decades of failure the Taliban now rule. Then there was the debacle in Iraq and Libya. Notice that America went to war on some of the poorest nations and despite its huge wealth, and great military might, it lost. In Ukraine a proxy war is being fought that the U.S. is losing. And now in Iran.

Non-state actors play increasingly prominent roles, especially the military-industrial complex which President Eisenhower warmed about. Today’s U.S. military budget is almost a trillion dollars and not subject to audit like other parts of the federal government. It will soon rise 50% with much of it profiting big corporations, including big oil and technology.

How does war impact health? First there are the direct casualties both military and civilian. War targets non-combatant civilians and destroys civilian infrastructure. Close to thirty million lives were lost in the Soviet Union during the Second World War with more than half being civilians. Major wars produce substantial declines in life expectancy. This was seen in France for both World Wars. Japan’s life expectancy dropped to 25 years at the end of World War II.

There were similarly high causalities in Britain. Considering British life expectancy before and after both world wars, there were huge gains . Reasons include the social solidarity produced in coping with the traumas.

While it is usually the rich who wage war, it is mostly the poor (and young) that die. Today those on the battlefield are not the wealthy who plan the conflict and plan to profit from it but those lower down in the hierarchy who don’t have a way out either by force or economic pressure. In ancient times those leading the charge were generals and monarchs. No more.

Besides the direct impact on morbidity and mortality there are indirect effects including malnutrition, infectious diseases, together with an increase in mental and behavioral disorders (witness the rise of Post-Traumatic Stress Disorder PTSD). Inciting factors include physical and sexual trauma, family separation, deaths of loved ones, damage to the environment, loss of employment and education, forced displacement, witnessing atrocities, and uncertainty about the future. Wars stress not only pregnant women and their progeny but also future generations.

Surviving military personnel, many of whom were noncombatant civilians before being forced to join the military, suffer from PTSD, substance use and suicide as well as physical disabilities.

Who wins a war and who loses matters. The United States, despite fire-bombing Tokyo with over hundred thousand civilian casualties, and the huge carnage of dropping two Atomic Bombs, won the war and was a hero. If it had lost, then the country would have been tried as a war criminal.

Paradoxically, the US-Allied Occupation of Japan after the war put in place policies of demilitarization, democratization and decentralization that levelled the inequality there and resulted in the greatest decline in death rates ever seen. As a result Japan became the world’s longest living nation in 1978.

Aggressors want to limit loss of their human lives, so mechanisms of war are changing quickly today. Electronic warfare with drones and missiles have become major players. Nations have strong incentives to develop nuclear weapons as their presence seems to protect against invasions by outsiders. Consider North Korea as an example.

Consider too the current debacle in Iran where the United States joined Israel in the invasion. Despite the U.S. military top brass advising against the invasion, the Commander-in-Chief acted. This war is costing Americans several billion dollars a day with no victory in sight. This outlay could fund many social programs and immensely improve U.S. health. And then there’re all the costs in life and limb to Iran’s neighbours and many others around the world, including from malnutrition.

What is to be done? While wars have much to teach us, returning to forager-hunter societies is not possible today. Curbing the power of the non-state actors by lessening the profits they get from producing the implements of war would do much to counter going to war. The international arms trade fuels much harm. Other ways include fostering diplomacy to resolve conflicts and abiding by internationally agreed upon rules. Addressing economic inequality, the root cause of war, would have the greatest impact. But humans seem intent on increasing the gap between those with too much and the rest of us. The United Nations concept put in place after World War II has lost its ability to foster peaceful solutions because of neoliberal policies implemented in the last half century. Through championing so-called free-market forces the rich have become fabulously wealthy creating greater inequality, and control the political process through buying politicians and governments.

Each of us has to use the means at our disposal to further recognition of the harms of aggression and war. The last parts of my two recent books contain much pragmatic material. Gaining consensus is more difficult today with so many media distractions. But doing nothing will also accomplish nothing.