Which U.S. conflict was characterized by massive bombing campaigns and high casualty rates, especially among civilians?

The Vietnam War is characterized by massive bombing campaigns and notably high casualty rates, particularly among civilians. The U.S. conducted extensive air operations, including the use of napalm and artillery, leading to widespread destruction and significant loss of life in both military personnel and civilian populations. Operations such as Rolling Thunder involved relentless bombing of North Vietnam and later, the Ho Chi Minh Trail in Laos and Cambodia, in an attempt to disrupt North Vietnamese supply lines. The civilian impact was profound, with reports indicating millions of Vietnamese deaths and long-lasting effects on the country's landscape and infrastructure, as well as on the psychological well-being of the population.

In contrast, while the Korean War involved significant military engagements, it did not reach the same level of widespread civilian casualties or bombing destruction as seen in Vietnam. World War I also had high casualty rates, but its context and use of technology differed substantially compared to the Vietnam War. Lastly, the Spanish-American War was relatively short and did not involve the same scale of bombing or the civil devastation that characterized the Vietnam War. Thus, Vietnam stands out for its combination of extensive aerial bombardment and tragic civilian consequences.