Smallpox decimated the Native American population

The argument

When European people first came to modern-day North America, they brought smallpox with them. While the disease had been around for centuries in Europe and Asia, the indigenous peoples of North America had no immunity at all. That asymmetry is the whole of the catastrophe. In populations where a disease has circulated for generations, many adults have survived it and a proportion of each new cohort does too; where it has never been present, every person is susceptible at once, and the sick cannot be nursed because those who would nurse them fall ill at the same time. This destroyed the indigenous populations, killing people in their tens of millions. Over a century, 90 to 95% of the indigenous population were killed. A loss on that scale is not a demographic setback but the removal of the societies themselves — of the people who held their knowledge, worked their land and defended their territory. The indigenous population of Mexico went from 11 million to one million people, playing a significant part in the fall of the Aztec Empire, which is the clearest instance of the disease deciding an outcome that force alone had not. The Smallpox pandemic is notable not only because of the amount of people it killed (roughly 56 million, the second largest in history) but because of the way it symbolises the utter destruction colonialism inflicted on indigenous populations. The comparison the figure invites is with what the disease did as well as how many it killed: a pandemic that removes nineteen people in twenty from an entire hemisphere's population, and clears the ground for the conquest that follows, is not merely the deadliest kind of event but the most consequential. On this argument, smallpox is the worst pandemic in history.

Premises

Counter-arguments

The catastrophe the argument describes is real and staggering, but the specific conclusion that smallpox is 'the worst pandemic in history' is contested, and the argument's own figures work against it. It puts the toll at roughly 56 million and calls this 'the second largest in history' — which, by its own metric of absolute deaths, concedes that smallpox was not the worst. 'Worst', in any case, depends on the measure chosen: absolute deaths favour some candidates (the Black Death, the 1918 influenza), proportion of a population favours others, and duration favours others again, and the argument does not defend the metric on which its claim would hold. There is also a causal overstatement. The collapse of Indigenous populations after 1492 — the 90 to 95 per cent mortality it cites — was produced by several introduced diseases acting together, including measles, influenza and typhus, not by smallpox alone, so attributing the whole depopulation to smallpox overstates that one disease's share. And a series of epidemics spread across a continent over more than a century is arguably a long demographic catastrophe rather than a single 'pandemic' event of the kind the comparison has in mind. The devastation is not in doubt; the superlative and the sole attribution to smallpox are.

Rejecting the premises

[Rejecting P2] The post-1492 collapse was caused by several introduced diseases together — measles, influenza and typhus as well as smallpox — so attributing the whole 90–95% mortality to smallpox overstates that disease's specific share. [Rejecting P1] The argument's own figure calls the toll 'the second largest', which by its own metric is not the worst, and 'worst pandemic' depends on whether one counts absolute deaths, population share or duration — a choice it does not defend.