9 Costliest and Deadliest Wars in Modern History

War, as defined by Merriam-Webster as 'open and declared armed hostile conflict between states or nations', is ugly and devastating both economically and in terms of the cost of human life. War is also, sadly, persistent and prevalent. As Chinese military strategist Sun Tzu stated in his book “The Art of War”, from around 500 BC, “War causes inflation and makes people poor,” especially referring to periods of prolonged war. Military strategists still learn from his book today.

While there are certainly conflicts which have caused more death than some of the listings below - such as the Taiping Rebellion of China that left 20 million dead, the An-Lushan Rebellion that killed 13 million, and the Mongol Conquests that killed 40+ million - it has proven impossible to accurately deduce the costs of these wars. Here, we've taken a look at the tragic conflicts which were both the deadliest and costliest, based on empirical data that draws on both the financial drain and the death toll of more modern wars and conflicts.

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9 Syrian Civil War - (Cost: $25 billion) (Death Toll: 191,000)

Syria is the latest Middle Eastern country that everyone is following in the media and at home, and for good reason. With ISIS and the United States’ recent decision to bomb the terrorist group with help from five Arab factions, and the three year civil war, things have been in utter turmoil in Syria for quite some time.

On March 15, 2011, Syrian protesters rallied against the regime of President Bashar Assad. It started as a peaceful uprising until Assad cracked down with vicious force and found the protestors retaliating. The uprising became an armed insurgency by July. Three years on, neighboring nations have come in to contribute weapons, fighters, funding, and assistance to both sides. Russia, Iran and Lebanese militia Hezbollah back the government, while the Western powers, the Gulf states and Turkey support the various rebels. As the civil war has displaced 2.5 million people and killed another 191,000, this is a devastating and costly war both in terms of finances and lives lost.

8 American Civil War - (Cost: $84 billion) (Death Toll: 750,000)

For 110 years, the American Civil War’s death toll stood at an exact 618,222 men killed - by far the greatest toll of any war in American history. A 2012 census study that has gained wide scholarly acceptance raised that number by 20%, to 750,000, further elevating the significance and devastation of the already epic war.

The war between the northern Union and the southern Confederacy was, on the surface, a conflict over abolishing slavery, while the real war was over political and monetary control. The bloody 4-year war became an expensive mass of politics and ideology that often had family members fighting against each other. This time of conflict also birthed some of the 19th century’s most influential Americans, such as Ulysses S. Grant, Robert E. Lee, William T. Sherman, and many more.

7 Iraq/Afghanistan/Pakistan War - (Cost: $3.4+ trillion) (Death Toll: 300 - 350,000)

Recent studies show that the cost of the War on Terror, including both the Iraq and Afghanistan wars, are the most expensive wars in human history. The direct costs have been estimated at between $3 and $4 trillion dollars, while veteran benefits and other expenses will in the end raise that cost to $6 trillion, or the equivalent of $75,000 for every American household.

Though the Iraq war began under what are generally accepted to have been false pretenses (that they possessed nuclear warheads), the outcome of the war led to the overthrow and execution of Saddam Hussein. Still, the war is largely seen as a failure since the escalation of insurgency spilled over into the Syrian Civil War once Americans departed, and many argue that the country is worse off than when the US went in. The official death toll of the bloody conflicts varies greatly, but there is no doubting that this conflict is one of the most brutal in recent history.

6 Soviet War in Afghanistan - (Cost: $106.3 billion) (Death Toll: 958,000 - 1.6 million)

The Soviet war in Afghanistan lasted 9 long years, from Christmas Eve 1979 to February 15, 1989. It was part of the Cold War and was fought between Soviet-led Afghan forces and the multinational insurgent group Mujahideen. The Mujahideen received military training from Pakistan and China, as well as weapons and billions of dollars from the US, UK, Saudi Arabia, and Iran.

The Afghan government secured a treaty in December 1978 that allowed them to call on Soviet forces to fight against Mujahideen rebels. Foreign ministers from 34 Islamic nations condemned the Soviet’s intervention, calling for their immediate withdrawal. This would not happen until 1987, after Mikhail Gorbachev came on to the scene and introduced his ‘new thinking’ on domestic and foreign policy. The conflict has sometimes been referred to as the “Soviet Union’s Vietnam War,” and while the military death toll was large with 108,000 killed between the forces, the bigger tragedy was the death of between 850,000 and 1.5 million civilians.

5 Iran-Iraq/Persian Gulf War - (Cost: $109 billion) (Death Toll: 1 million)

The Gulf War, codenamed Operation Desert Shield and then Operation Desert Storm, was a war waged by a coalition of 34 nations against Iraq in response to Saddam Hussein’s invasion and annexation of Kuwait in 1990. The war was one of the first to receive around-the-clock TV coverage, and cost a huge $109 billion in just 6 months.

While the death toll was not very high in the Persian Gulf War, if you consider the 8-year Iran-Iraq War from 1980 to 1988 that led up to the Gulf War, you have the 20th century’s longest conventional war, and a very bloody one, resulting in over 1 million deaths. Iran faced an economic loss of $627 billion after the Iran-Iraq conflict, while Iraq faced a $561 billion loss.

4 Korean War - (Cost: $364 billion) (Death Toll: 1.2 million)

The Korean War was waged between UN and US-backed South Korea against China-backed North Korea, also assisted by the Soviet Union. The war arose after the division of Korea at the end of World War II and the tensions of the Cold War that developed. Korea was ruled by Japan from 1910 until the end of the war. In August 1945, the Soviet Union declared war on Japan, and agreed with the US to occupy Korea north of the 38th parallel. US forces occupied the south, and both governments claimed to be legitimate governments of Korea, with neither side agreeing on a permanent border.

The conflict escalated into open warfare in 1950. The result ended in an indecisive victory for either group, though the death toll and monetary cost was monstrous. Over 500,000 fighters died directly from the 3-year war, while many more civilians were massacred on both sides. The war has been seen as a civil war and a proxy conflict in the Cold War between the US and the Soviet Union.

3 Vietnam War - (Cost: $788.5 billion) (Death Toll: 790,000 - 1.14 million)

The Vietnam War will always be seen as the war that America lost, and also as one of the messiest wars from start to finish. Fought from 1965 to 1975, the conflict scarred the American and Vietnamese nations, both physically and mentally. The US pulled out of the country just prior to being destroyed.

While the war saw widespread US public support in the beginning years, by the time American veterans returned home from the horrible conflict they were met with contempt and non-existent support. The economic toll was huge, but the loss of life was far greater. While the US lost 58,220 soldiers, and had 303,644 wounded, the Vietnamese people faced a far greater onslaught of death with hundreds of thousands of military men and civilians dead by the end of the conflict.

2 World War I - (Cost: $357 billion) (Death Toll: 17 million)

One of the deadliest conflicts in history, the Great War began in 1914 with the US joining in 1917. What started as a conventional trench war saw unprecedented technological advances by the end of the conflict in 1918, helping to exacerbating the casualty rate to an unprecedented 10 million combatants and 7 million civilians during the 4-year war.

The immediate trigger for the war was the assassination of Archduke Franz Ferdinand of Austria on June 28, 1914. He was the heir to the Austro-Hungarian throne, and his death set off a diplomatic crisis between them and the Kingdom of Serbia. Soon, the war spread worldwide, driving in all of the world’s economic powers, which were divided into two opposing alliances: the Allied Powers of Britain, France, and others, and the Central Powers of Germany, Bulgaria, Austria-Hungary, and Turkey. Ultimately, more than 70 million military personnel were mobilized in one of the largest wars in history.

1 World War II - (Cost: $4.1 trillion) (Death Toll: 72 million)

World War II was the deadliest conflict in human history, resulting in the deaths of between 50 and 85 million people. It pitted the Allies against the Axis, included all of the great military powers, and was marked by the mass deaths of civilians, including the Holocaust, the atomic bombings of Hiroshima and Nagasaki, and more.

The Empire of Japan was already at war with the Republic of China in 1937, but the world war is generally regarded as beginning with the invasion of Poland by Germany on September 1, 1939. The December 1941 Japanese attack on Pearl Harbor brought the United States into the war. WWII is probably the most catastrophic war in world history, both economically, and especially as the death toll showed the destruction mankind is capable of.

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