Friends don’t let friends get their city-states captured. In Civilization V, city-states were pretty much pointless wastes of land, only there to be paid off for favors in the World Congress. In Civilization VI they’re a lot more viable, much like the barbarians, and can serve as powerful allies or even more nefarious foes.
You now utilize an envoy system to sow favor, in which you send delegates to their capital, and after one, three, and six envoys you get certain district-related bonuses. This can be tremendously useful, too, as once you become a city-state’s suzerain, you can then receive bonuses to some yields, special luxuries, and even the ability to levy their entire army for a fee. This could severely shift the tide of a particularly egregious war.
More often than not, though, your city-state buddies will be prey to other civilizations looking for a nice plot of land and precious resources. If the time comes, like it did in my game, (where Norway decided it would stomp all over Toronto) you can actually restore your friend to their former glory by sending some units over there and taking it like it was a city. When you finally break its defenses, you will have three options instead of the usual two.
You can either keep the city for your own, raze it to the ground, or Liberate it, which is the option we’re most concerned with here. Liberating the city-state will act as a counter to the damaging Warmonger penalty you would usually get for a raze, or claiming the city for your own. And, of course, I’m sure the city-state you just saved will be in your debt. It’s a useful tactic if you want some good allies in-game.
For more Civilization VI tips and tricks, keep it locked right here at Twinfinite with our wiki.