I was reading up on the slave trade as part of the merchant war that is building in intensity. I’m not going to argue the historical fact of this, but according to a fairly academic source, the brutal nature of the French Caribbean sugar plantations (huge slave colonies) caused the slaves to revolt. The slave revolt turned Saint-Domingue into the free state of Haiti. The loss of Haiti caused a shortage of sugar in Paris which in turn led to riots. It was these riots that turned the French Revolution from a high minded endeavor into an authoritarian regime (the government needed to crack down on the riots, and then never let up).
Doesn’t matter if it’s right (though it likely is) -It’s still a heck of a story. It made me think - What imports are going on in various areas that if someone were to “turn off the tap” would cause rioting? I mean - we’re not talking about blocking flour, we’re talking about sugar. Sure it’s a need, but it’s a lot more of a want. Booze came to mind. If you have a region that is a major wine drinking culture (or beer) and all of a sudden they can’t get their alcohol, you’re likely going to see some discontent. Now discontent doesn’t turn into riots without overcrowding, but still.
Why do you need riots? Why do you need stuff like this? You having any trouble motivating your characters to get involved in the politics of their homeland? This is a mini-campaign in the making: Wine has become scarce in the home city. The last few merchant ships that would normally have had it have been carrying grain instead. The news is that there was a bad grape season in the wine country. After several months, the stores have been depleted, and the alternatives are also running low. The country’s national dish requires wine, and there just isn’t any to be had. The king is getting nervous, because a mob just burned down a wine distributor’s warehouse when they found it empty. The city is fraying at the ends. The party needs to go get some wine and deliver it safely. Along the way they learn that this was in fact just a ruse by the wine producers to cause unrest. They are stockpiling wine barrels which they will deliver as soon as the king’s evil cousin is put on the throne. Could a revolution succeed simply because the people wanted wine and one king could give it to them while the other couldn’t? Depends on how much they love their wine! Governments have fallen over lesser issues.