Two wars
By 
Deaths from the terrorist attacks on 9/11/2001: 2,977
Deaths in the USA from COVID-19 as of 9/08/2022 per the CDC: 1,044,461
Note that the latter figure is probably a considerable underestimate, because of COVID deaths being coded as something else. We’ve had about 1.3 million excess deaths since March of 2020. Some of these are from the secondary effects of the pandemic rather than COVID per se, and in a real sense are also COVID deaths, but the vast majority of the difference between the two figures is just undercounting.
One of the inevitable effects of getting old is that time telescopes and accelerates in various ways. The gap between today and 9/11 is exactly the same as the gap between 9/11 and the election of Reagan, but the first gap feels very small to me (I was 21 when Reagan was elected) compared to the second one.
The 9/11 attacks produced the necessary excuse for the Bush administration to engage in an invasion of another country that in the most important ways was really not very different from Putin’s invasion of Ukraine (obviously there are distinctions but they are fairly trivial in comparison to the similarities). Every non-fascist recognizes without any difficulty that the latter is a war crime of immense proportions.
Meanwhile the former remains for the Blob and its countless courtiers in the media a “policy error.”