[mikeash]

It wasn’t the first time. The USSR even killed a sitting Congressman in one of them. The US did nothing then either.

[mieseratte]

It is worth pointing out the US has also shot down a civilian airliner[0] of a non-friendly nation and it didn't escalate into war so perhaps accidental shoot-downs are not generally accepted as casus belli?

[0] - https://en.wikipedia.org/wiki/Iran_Air_Flight_655

[wbl]

And we apologized, paid money, and took responsibility.