Edit: Edited to state that this was not fire of combatants in a combat zone.
I'm sure that there were plenty of other times it happened, but, for a relativly well-know and documented incident in 1932, check out the Bonus Army[1]
[1] https://en.m.wikipedia.org/wiki/Bonus_Army#:~:text=The%20Bon....
That seems incredibly unlikely. Friendly fire incidents have been a fact of war, pretty much forever.
Friendly fire, _by definition_, is not something the Army _actively plans_ to do.
First item on this list: https://www.military.com/military-life/6-times-military-was-...
> 1863: The New York City Draft Riots > the governor [...] had to call in U.S. Marines.
As with so many aspects of American governance, they "solved" an either-or problem by implementing both ideas.
Not close to the first time. Kent State is one famous example. Countless people shot for trespassing on bases
By the way, if you want to split hairs and bring up examples like Kent State, the elephant in the room is the self-defense justification in a lot of these examples. Find a killing that occurred when a soldier believed their life to be in danger.
Well, no; we just weren't doing it using the military. Or at least weren't doing it using the military in a way that we got caught. The US government (and, I expect, nearly every government since the dawn of governments) has been killing people outside of "the battlefield" forever.
This is to say nothing of the many, many times the Army was used to clear natives from lands claimed by the US. Presumably, in most of those incidents, they were not considered American citizens. However, they definitely were in the most recent incident I can think of, the Wounded Knee massacre, which happened in 1980. That was the 7th Cavalry, and they killed 250 Lakota, including women and children.
The basics are that Al-Awlaki was (allegedly) a kind of pro-terrorist or pro extreme Muslim kind of preacher moving about the Middle East spreading his message. Possibly also hooked up with real terrorists / jihadis. A drone strike killed Awlaki and a second drone strike, a couple weeks later, killed his sixteen year old son. The US claimed killing his son was an accident - but that's pretty implausible. Years later, under Trump, a special forces team killed his eight year old daughter.
And union busting police? And modern police, before and after 2020?
This will continue until (1) the courts eliminate Qualified Immunity and (2) police unions have to carry liability insurance for all its members.
It is easy to get outraged at the military, but the police is way more harmful here.