The United Nations is an important Great Wonder that can be built at the end of the game after a civilization discovers the Mass Media technology. The construction of the United Nations opens up the possibility of a Diplomatic Victory, achieved when a civilization has been elected as the world leader.
Beyond the Sword added the Apostolic Palace. The civilization that builds it has its current religion united under one banner. The Apostolic Palace thus allows the possibility of Diplomatic Victory early in the game.
Once the United Nations has been built anywhere in the world, votes will begin being held every few turns. Every civilization participates in these votes, regardless of their strength. The number of votes that a civilization receives is determined by its population; the larger the population of a civilization, the more votes that its leader casts in United Nations elections.
Types of Votes
Secretary General Elections
The first United Nations vote will always be to determine which leader will be selected as Secretary General (see below for more information on the powers granted to the Secretary General). The civilization that builds the United Nations will always be one of the two candidates to stand for Secretary General; the other candidate for Secretary General will be the leader whose civilization has the highest population (or second-highest if that is the civilization who builds the United Nations). When voting for the Secretary General, each civilization will choose one of the two candidates to cast their votes in favor of, or can choose to abstain altogether. If one of the two candidates receives a majority of the total votes (including the civilizations who abstain), that candidate becomes the Secretary General. If there is no majority, the election is inconclusive and there will be another election for Secretary General again a few turns later. Nothing else may be accomplished until the United Nations selects a Secretary General.
When a Secretary General has been chosen, he or she can choose from a list of the following resolutions to put to a vote. After three such resolutions have been voted upon, there is a new election for Secretary General, and the process repeats. Unlike the simple majority vote to determine the Secretary General, all of the following resolutions require 60 percent or greater of the total votes to be adopted.
Adopting the Free Trade resolution removes all barriers to trade everywhere in the world. Trade routes function as though all civs have Open Borders with one another regardless of what their diplomatic situation may be.
Adopting this resolution causes an end to the proliferation of nuclear weapons. No civilizations anywhere in the world can construct nuclear weapons (although existing nukes do not disappear).
Adopting this resolution forces all civilizations to change to the civic Universal Suffrage, regardless of whether or not they possess the technology to do so normally.
Adopting this resolution forces all civilizations to change to the civic Free Speech, regardless of whether or not they possess the technology to do so normally.
Adopting this resolution forces all civilizations to change to the civic Emancipation, regardless of whether or not they possess the technology to do so normally.
Adopting this resolution forces all civilizations to change to the civic Environmentalism, regardless of whether or not they possess the technology to do so normally.
Adopting this resolution forces all civilizations to change to the civic Free Religion, regardless of whether or not they possess the technology to do so normally.
Declare/Stop war against X
This will cause all other civilizations to declare war on/make peace with a certain civilization.
The Secretary General may also put him or herself up for a Diplomatic Victory. With enough votes from the other civilizations of the world, he or she can win the game through becoming the undisputed leader of the United Nations and the world. Who said nice guys finish last?