Presbyterian polity was developed as a rejection of governance by hierarchies of single bishops (episcopal polity), but also differs from the congregationalist polity in which each congregation is independent. In contrast to the other two forms, authority in the presbyterian polity flows both from the top down (as higher assemblies exercise considerable authority over individual congregations) and from the bottom up (as all officials ultimately owe their elections to individual church members). This theory of government developed in Geneva under John Calvin and was introduced to Scotland by John Knox after his period of exile in Geneva. It is strongly associated with Swiss and Scottish Reformation movements, and with the Reformed and Presbyterian churches.
Presbyterianism uses a conciliar method of church government (that is, leadership by the group or council.) Thus, the presbyters (elders) govern together as a group, and at all times the office is for the service of the congregation, to pray for them and to encourage them in the faith. The elders together exercise oversight (episcopacy) over the local congregation, with superior groups of elders gathered on a regional basis exercising wider oversight.
Presbyterians typically have viewed this method of government as approximating that of the New Testament and earliest churches. However, sometimes it is admitted that episcopacy was a form of government that was used very early in the church for practical reasons. Some Presbyterians are more adamant, that prelacy is in itself corrupt and rebellious against the Word of God.
Presbyterianism is also distinct from congregationalism, in that individual congregations are not independent, but are answerable to the wider church, through its superior courts (presbyteries, synods and assemblies.) Also, the ordained ministry possesses a distinct responsibility for preaching and sacraments. Congregational churches are sometimes called "Presbyterian" if they are governed by a council of elders; but the difference is that every local congregation is independent, and its elders are accountable to its members, and congregationalism's wider assemblies are not ordinarily empowered to enforce discipline. Thus these are ruled by elders only at the level of the congregations, which are united with one another by covenants of trust. Reformed Baptist churches are sometimes organized to be governed by elders, on the congregationalist model.
The elders are persons chosen from among the congregation and ordained for this service. Beyond that, practices vary: sometimes elders are elected by the congregation, sometimes appointed by the session, some denominations ordain elders for life, others have fixed terms, and some churches appoint elders on a rotation from among willing members in good standing in the church.
In addition to sitting on the session and other church courts, ruling elders have duties as individuals. Again, Miller (1831) explains,
Ministers may be considered equal in status with the other elders, but they have a distinct ordination and distinct function. They are the primary preachers and teachers, celebrants of sacraments. There are sometimes further distinctions between the minister and the other elders. Some Presbyterian denominations enroll ministers as members of their respective congregations, while others enroll the minister as a member of the regional presbytery.
Until the 20th century, only men had been eligible for the ministry or eldership world-wide. This is widely not the case any longer; although it is usually considered a demarcation issue, distinguishing "liberal" from "conservative" churches that practice presbyterian government. ''See also: Ordination of women
The general assembly of a denomination often decides on what grounds a person may be ordained, but the ordination of ministers is the right of the presbytery, and the right to extend a call to a minister is the privilege of the members of the parish or congregation.
The office of deacon has different meanings among different presbyterian churches. In some churches, deacons exercise responsibility for practical matters of finance and fabric, either separately or together with the elders. In some cases deacons administer the welfare matters of the congregation, while a separate board of management or trustees administers the other material business of the congregation, such as its endowments, salaries and buildings.
The minister will usually chair or preside over the session. All elders have an equal vote in the session. In theory, the minister is not the head of the session; he or she typically enjoys only a casting vote. In reality, though, sessions often regard the minister as 'the leader'.
The officers of a presbytery are a moderator and a clerk. The moderator acts as chair of presbytery meetings and has a casting, but not deliberative, vote. As with the moderators of synods and assemblies, the moderatorship is a primus inter pares position appointed by the presbytery itself. The moderator is addressed as "moderator" during meetings, but his/her position has no bearing outside of the presbytery meeting and affords him/her no special place in other courts, although typically the moderator (if a member of the clergy) will conduct worship at ordinations and other ordinances which are seen as acts of the presbytery.
The clerk takes minutes and deals with the correspondence of the presbytery, and is often appointed for an indefinite term.
Presbyteries meet at a regularity between monthly and quarterly.
Often all members of the constituent presbyteries are members of the synod. Like the commissioners to presbyteries, the commissioners to synods do not act on instruction from their congregations or presbyteries, but exercise their own judgement. A synod also has a moderator and clerk, and generally meet less often than the presbytery.
Some presbyterian churches have no intermediate court between the presbytery and the general assembly.
The clerk and deputy clerk of the general assembly administer the minutes, correspondence, and business of the assembly. In some cases a separate business convenor is appointed to deal with the agenda. General assemblies meet less regularly than their subordinate courts, often annually.
The powers of the general assembly are usually wide-ranging. However, they may be limited by some form of external review. For example, the rules of the Church of Scotland include the Barrier Act, which requires that certain major changes to the polity of the church be referred to the presbyteries, before being enacted by the general assembly.
As a form of church governance, small-p "presbyterian" polity is not limited to those denominations that call themselves Presbyterian. The term has been used to describe representative democracy in churches.