In the short time it fought in World War I, from 1917 to 1918, America lost roughly 53,000 military personnel to combat deaths. In the four years of World War II, the number was approximately 400,000. In the extended 19-year period of the Vietnam War, it was 58,000.

In the almost 15 years since 9/11, in fighting primarily in Afghanistan and Iraq, America has lost approximately 5,375 lives.

This smaller number of combat fatalities is largely due to the smaller number of U.S. forces at risk in Afghanistan and Iraq, as well as the inability of the enemy in these two nations to field a credible military force. We also haven’t seen the fielding of opposing large, well-trained armies, squaring off in major set-piece battles, in which thousands at a time are slaughtered with air strikes, artillery, and direct assaults on heavily fortified positions.

In fact, examining two specific measures of success in caring for combat casualties paints a more accurate picture with regards to these lower casualty rates. The case fatality rate—the percentage of wounded who die from their injuries—for U.S. casualties is the lowest it has ever been in a major modern conflict (nine percent in Iraq and Afghanistan, as compared to 19 percent in World War II and 15 percent in Vietnam).

Furthermore, while some combat fatalities are not preventable, such as casualties who suffer, for example, a direct hit from an RPG or an artillery shell, others clearly are preventable (such as a casualty who dies from a gunshot wound to the lower thigh where they bleed out). Preventable combat fatalities in some U.S. units and allied nations (notably, Canadian Forces) are now the lowest in the history of modern warfare.

How did this happen?

Tactical combat casualty care

The likely explanation, and driver, for this decrease in combat deaths is found in the field of military medicine, specifically in the adoption of tactical combat casualty care (TCCC).

Although U.S. and coalition forces today have unsurpassed combat hospitals and evacuation systems, survival for casualties hangs in the balance before they arrive at the first hospital. Badly wounded casualties often need immediate care, at the scene, if they are to survive their wounds.