The World Congress appears once the Printing Press is discovered by a nation that has already made contact with all other nations. Thus, it's possible for this to occur in the early Renaissance. In practice, the organization often appears later in the Era.
The nation that first gets the Printing Press and contacts is the first one to Host the World Congress. They preside over the meetings by proposing the initial Resolution to be considered by the group.
Each nation gets some level of representation in the congress. The Host always gets a bonus number of Delegates (and these are used to help vote for Resolutions you like or to try and shut down Resolutions that hurt your interests). There are multiple ways to get more Delegates, and most people in the Congress are going to find ways to improve their influence, because there are some powerful options if you get a big edge over your rivals.
How to Get More Delegates
- When the group of nations reaches a new Era, everyone gets more Delegates in the World Congress
- Being Host of the World Congress grants two more Delegates
- City-State Allies grant you their Delegates
- If the World Religion Resolution passes, any nation with the majority of their cities following that religion gets two more Delegates
- If the World Ideology Resolution passes, nations following that Ideology get two more Delegates
- The United Nations' votes for World Leader end the game if someone wins; otherwise, the votes are tallied, and the two highest nations receive one more Delegate each
- Every Spy that you assign as a Diplomat earns you a Delegate until that Spy is reassigned
Over time, you can expect the nations with the highest Delegates to pass Resolutions that give themselves even more power. Their goal is to secure World Religion and World Ideology for themselves; this gives them enough Delegates to push their agendas even further. They'll likely be on top during the World Leader votes, and then it's only a matter of time until the free Delegates they receive during those votes push them over the top into a Diplomatic Victory.
Are You Trying to Win Via Diplomacy?
+ Take Patronage to help with City-State Alliances
+ Freedom is a good Ideology to pursue, with multiple City-State benefits
+ Spread your Religion early to make World Religion an easier sell
+ Use Diplomats constantly
+ Explore and rush to research Printing Press, to aid your chances of being the first Host
– Don't antagonize City-States, even when it seems to be in your short-term interests
– Don't make enemies unless you have to; nations that don't like you bring up Resolutions that harm your people
If you’re trying to win via Diplomacy, don't use Spies for anything except Diplomatic purposes. The free Delegates are wonderful, and Diplomats also let you know how the target civilization is going to vote for the next set of Resolutions. That allows you to avoid wasting votes on bills that are going to already pass or fail without your assistance; you can put all of your weight where it's needed the most—maximizing your influence over the World Congress!
When considering Resolutions, look over each one carefully; their descriptions are already helpful, but that's not all you're looking for. As you ponder each choice, highlight and see what the selections say. They'll tell you if any nations would be upset (or grateful) if you propose specific Resolutions. Doing this gives you an early idea for how much support it's going to take to pass anything. If multiple nations are opposed, you're unlikely to succeed without help.
From the Diplomacy Screen, you're able to look at the World Congress at any time after it's founded. In the top right, the window tells you how long it'll be before the next World Leader proposal and how many Delegates it's going to take to win.
From there, the Host can also rename the World Congress/United Nations. Give the title a bit more flair if you'd like!
You can see how many Delegates each nation controls and use your Diplomatic contacts to tell how people are going to vote (just highlight the Resolutions that are coming up). If you have enough time, it's possible to write down the votes that you know about, shift your Diplomats over to new Capitals, and find out more about other nations' votes before the next meeting. This is a hassle, but it's useful when extremely important Resolutions are pending.
When the time comes to win, you're going to stand alone. Nations like to vote for themselves as World Leaders, even when they like you. So, having City-State Allies is essential. Impress them, scare them, or buy them off. Do whatever you have to. Do not, however, conquer them. Your nation's size, cities, and wealth mean nothing (officially) on the floor of the United Nations. Make Allies and keep them on your side.
If You Can't Be Number One
The nation (excluding the Host) that has the highest number of Delegates gets to propose a Resolution for each meeting. That means that they're almost as powerful as the Host. Always try to edge out the competition even if you have no hope of gaining the Host's seat anytime soon. When you have money to spare, buy Influence and Allies with City-States in the couple of turns before a vote. That won't leave rivals much time to erode your City-State support by buying them off, using their Spies, or attacking and conquering the cities in question.
When the majority of civilizations advance into each new Era, there's a vote to change the Host of the World Congress. That's when you have your chance to move to the top. Make sure that the existing Host loses as many votes as possible—if you're able to buy off City-States that are Allied with them, you've effectively scored two Delegates toward your succession (by stealing one away from your rival and adding it to your pool).