What should be my objectives when going to war with another civ?

Question

In Civ4, going to war with a more powerful army than your neighbors' was quite profitable. If a neighboring civ started to expand into your territory, you could go to war and raze their cities to free up some land and claim it later with a settler; or you could take over the city. In both cases, claiming more land counted towards global domination victory (the one where you own more than 80% of land, IIRC).

In Civ5, war does not seem so much profitable. There's a heavy penalty for annexing cities; and large empires are much harder to manage than in the previous game.

When I have a larger and more powerful army than the other civs, I can see that going to war can have the following uses:

• Bully the other civ by hitting its cities long enough that they will ask for peace giving you lots of resources.
• Kill enemy units in order to get culture
• Buy the friendship of city-states by helping them fight off a warring civ.
• Of course, there's the world domination victory and all your base are belong to us.

But then again, all of these do not seem profitable reason and do not seem to make for the cost of building a powerful military to begin with.

I feel like there's a purposed use to military in Civ5 other than simply crushing the other civs. Civ5 is not StarCraft... Right ?

Questions:

• What should be my objective when going to war with another civ ?
• When to accept a peace treaty ? When is it time to stop the war ?
• What's the outcome of a war that you call profitable ? Culture, Gold, Land, Resources, Friendship with City-States ?

Answer 1

There are many reasons to go to war with another Civ:

• Take their territory and resources - although the game is more balanced towards making small Civs profitable than ever before, in most cases having more territory/cities/resources can still give you a big advantage.
• Halt the progress of another Civ who is doing better than you in some other area - if you have the military, you can stop a Civ who is doing better in technology or culture but who is weak militarily.
• Defending allies or forging new alliances - war is a powerful way to increase your reputation with allied civilizations. Allies can make war against you more difficult, and they'll be more receptive to trade agreements that are beneficial towards you.
• Nip a potential adversary in the bud - the AI in particular is terrible about unit tactics, so you may be able to provoke them to attack you and devote resources to war before they're completely ready.

Depending on why you're going to war, your goals/result will differ. You may wish to simply weaken their army, force them to give you money or other resources, or take a strategic city, but if you're going for a Domination victory, you're going to want to capture or destroy all of their cities, despite their (likely) pleas for peace.

Be wary of growing too large too quickly, as happiness is critical to growth, and extended war and capturing cities leads to rampant unhappiness. If you devote too much of your Civ's resources towards building and maintaining an army, you may fall behind in other areas, giving others room to outpace you.

I tend to prefer to puppet captured cities (instead of razing or annexing them) as this tends to provide a pretty good balance between the benefits of having more territory, resources, and population and the detriment of unhappiness due to size. There may be cities that are just worthless (ie, population 1 or 2 cities in poor positions) and need to be razed, or cities that are extra valuable (ie, high population cities with wonders or other beneficial buildings) that you'll want to keep tighter control over.

Unit tactics have also changed significantly since Civ4 - in that game, you wanted to build large stacks of units to march across enemy territory with at least moderate losses. In Civ5, if you focus on a few powerful front-line defensive units coupled with ranged attacks from siege units, you'll find that your investment in units is small compared to enemy losses. Siege units in border cities can make mincemeat of overzealous enemy armies once war is declared.