Master of Orion II: Battle at Antares/Diplomacy and intelligence

"War is merely a continuation of policy by other means"

- [http://en.wikipedia.org/wiki/Carl_von_Clausewitz

In MOO II diplomacy may be a continuation of war by other means. Most importantly:
 * It provides information about your opponents from the time when you first make contact (and they get similar inormation about your empire).
 * Espionage and sabotage are often powerful weapons, especially in the early game when warships are slow and weak.

These factors make "diplomacy" important even for Repulsive empires, whose options in negotiations are limited to declaring war and surrendering. This page summarizes the other options available to non-Repulsive empires.

How contact is made
Contact is made between 2 empires when either of them is in a position to send ships without Extended Fuel Tanks into systems occupied by the other. This arises when either empire occupies a new system in the right place (by creating a colony or an Outpost) or when either empire discovers improved fuel cells which extend its ships' range.

Contact can be lost if someone (either empire or a third party) destroys or conquers the last colony or Outpost in a system and no other systems ocupied by either empire are within either empire's ships' range. Contact can later be re-established by the means described above.

Diplomatic negotiations
All can by initiated by your empire or another one. All are usually forbidden in online games between human players, to prevent collusion.

AI empires become impatient and will refuse to talk for a while if you pester them with too many conversations in a short time - especially if the conversations are unfriendly or lead to nothing.

Tech trades
One side sees to gain a specific tech and the other makes various offers.

This can be frustrating for human players, as the game offers you a fairly small list of randomly chosen techs to give as part of a trade. You can usually find oneof the ones you're willing to trade if you're persistent, but there's no guarantee that you will.

Trade Treaty
Eventually increases both sides' money income, although initially there's a decrease. It takes about 5 turns to break even, except  Fantastic Traders get into profit in about half that time.

Research Treaty
Eventually increases both sides' RPs, although initially there's a decrease. It takes about 5 turns to break even, and Fantastic Traders have no advantage in Research Treaties

Peace Treaty
Ends a war, for a while at least. Both sides undertake not to attack each other for a specied number of turns; breaking this promise damages your reputation with other AI players. If you propose a Peace Treaty, an AI players may ask for a "sweetener", e.g. money of a tech; human players do not get the opportunity for this mild extortion. While a Peace Treaty is in force either side may send warships to the other's systems without automatically starting a battle or blockade.

Non-aggression Pact
Both sides undertake not to attack each other, with no time limit. If the treaty lasts long enough diplomatic relations between the empires improve, which makes further negotiations more likely to succeed. While a Peace Treaty is in force either side may send warships to the other's systems without automatically starting a battle or blockade.

Alliance
Like a Non-aggression Pact but with additional benefits and obligations:
 * Each side's ships' range is extended as if the other's colonies and Outposts were its own.
 * Your allies expect you to help them in wars. Failure to do so causes diplomatic relations between the empires to deteriorate, and eventually to cancellation of the Alliance. Too bad if you're allied with 2 empires and they go to war wiht each other.

Make demand
One side asks for something for nothing. If the relationship is really friendly, this might not harm the relationship, although the side making the concession will probably expect a favor in return later.

Some are sometimes made by an ally, but other empires may make them too:
 * Declare war on a 3rd party
 * Make peace with a 3rd party
 * Break alliance with a 3rd party

Some are reasonable but perhaps optimistic (if the side making them had real power, it would simply open fire); but they may be made by a player who wants to avoid 2 or more simultaneous wars: The system must be one that is occupied by the player making the demand.
 * Stop spying
 * Remove fleet from specified system

The remaining demands are naked extortion: Including all colonies, with their populations and buildings. That 5% of the other empire's gross income, not their surplus. Since this would usually be crippling, the answer is usually "No"; war is a common result. "... or your empire will be taken away." Yes, that's what they say. Apparently human players can't make this demand to AI players.
 * Demand tech
 * Demand system
 * Demand 5% tribute per turn
 * Demand 10% tribute per turn
 * Demand support in the next Galactic Council meeting

Make gift
An empire may do this to persude a more powerful empire that peace is more profitable than war (who do they think they're kidding?), or an empire that wants to win a council vote may do it to win friends. A gift may be one of: These last 2 demonstrate total subservience.
 * Money
 * A tech
 * 5% of gross income every turn
 * 10% of gross income every turn