This is like that episode of the Simpsons when Apu is getting his citizenship and taking the quiz, they ask him the cause of the American Revolution and he starts going through a list with nuanced analysis. The testmaster stops him and tells him: "Just say slavery." There were some other very minor causes, but slavery was the biggest.

Similarly, you can just say illegal purchases. The other things have been largely debunked. Interestingly, you didn't even mention the giant primary use case of buying illegal things.

Er, wasn't the one-word cause of the American Revolution "taxation" ? (The one-word cause of the American Civil War would probably be "slavery", though).

> Er, wasn't the one-word cause of the American Revolution "taxation" ?

No, “disenfranchisement”. Read the Declaration, it was about usurpations of the right of the people to govern themselves. “No...without representation” is the key part, not “taxation”.

That's been inverted for propaganda purposes by modern anti-tax activists.

But, in a any case, “slavery” would have to be the Civil War, the Texas Revolution, or—indirectly, by way of the previous item—the Mexican-American War.

I think black market purchases fall pretty clearly under #2 above.