A pact is simply an agreement between two parties, typically alliances. Pacts between alliances are signed by a representative - a Foreign Affairs representative, known as an FA - from each alliance contacting a representative from another alliance, and both representatives coming to an agreement on how the two alliances will interact with each other over the upcoming set. Pacts usually contain the type of the pact as well as certain conditions that must be met by both alliances. Pacts must be signed by both alliances to become valid. Most pacts are only valid for the reset they are signed for, and therefore must be renewed by both parties as each reset comes to an end; however, alliances may also choose to have pacts auto-renew themselves, to ease the burden of communication between the two alliances. Some pacts may generally be used across the board, while others may contain additional conditions, and are used for only certain alliances--the way pacts are handled is entirely up to the alliances. There are several types of pacts that have been created and agreed to by the established alliances through the years.
Non-Aggression Pact (NAP)
This pact simply states that the two alliances agree not to attack each other in any way. This pact is regarded as more of a pact of convenience than anything else. It is generally accepted that this pact may be broken at any time for any reason (usually for a Defense Pact), and the political consequences are generally light.
Unbreakable Non-Aggression Pact (uNAP)
This pact is considered the most important pact. This pact also states that two alliances agree not to attack each other, but that it also may not be broken for any reason. This pact is usually only signed between alliances that have worked for better relations over a long period of time. The political consequences for breaking this pact are usually fatal, and far-reaching. Breaking this pact for any reason is a serious violation of trust among alliances, and the backlash is usually immediate. To break this pact would mean to tell other alliances that your alliance's word means nothing, and other alliances may follow suit by breaking off all relations with your alliance, and most likely attacking you.
Defence Pact (DP)
A defence pact is signed between two alliances who decide to come to each others defensive aid in times of war. These pacts may not be used against a uNAP alliance. There are two types of defence pacts.
Limited Defence Pact (LDP)
It is between two alliances that agree to defend each other, but each alliance has the ability to refuse aid requests from the other alliance. This is popular amongst netgaining alliances who may not want to be forced to enter a war if they are doing well.
Full Defence Pact (FDP)
It is signed between two alliances that agree to defend each other, and each request for military aid must be met.
Offence Pact (OP)
This type of pact is rarely used among alliances, especially those involved in coalition warfare, but the general premise is that two alliances have agreed to help each other in attacking another alliance, or group of alliances. This pact may also not be used against uNAPs.
A new pact type still being developed by alliances. Grabbing pacts allow for landgrabbing between two alliances that are otherwise pacted. Grabbing pact terms vary and may be attached to any type of pact. Though when attached to a NAP, a grabbing pact will generally only allow for a specific period of time in which LGing may occur. When attached to pact types other than a NAP, grabbing pacts may are designed for allowing land exchanges between alliances while maintaining peaceful and even allied relations between the two alliances.
Any pact between alliances may include certain voidable terms, but voidable terms are generally restricted to uNAP pacts.
One-Sided Void Terms
One-sided void terms provide that a specific alliance to the pact may void the pact under certain specific conditions. The other alliance to the pact does not have the option to void the pact.
Mutual Void Terms
Mutual void terms allow that either alliance may void the pact under certain conditions. For instance, the pact may be voidable if either alliance attacks the other's DP ally or if either alliance attacks a specific other alliance.