Polity is necessary for people to live together. Although forms of polity in society vary the form of polity used is bound by what people accept and follow as common law, that which holds society together. Generally speaking, in society polity is divided into practice on the local, state and national levels.
In Christianity the Church also orders her life together using polity. The Catholic Church follows an hierarchical or episcopal order of polity. The names of some protestant denominations are directly related to their understanding of polity, ie, Episcopal, Presbyterian, Congregational. Schisms in church history have often been related to matters of polity as they have been related to matters of doctrine. The two, in fact, are intertwined, just as in secular government questions of polity are derived from the Constitution. However the Church or protestant denomination or sect understands and follows its polity that is how that group orders her life together.
Lutheranism has historically placed doctrine on a higher level than that of polity. Still, there are unanswered questions of polity that continue to fester and which may be traced back to the time of the reformation (historical developments following the reformation, such as the Enlightenment, have only exacerbated these questions). To the chagrin of Lutherans, they are sometimes characterized by those outside as being followers of "Luther," which, in itself is as much an observation of polity as it is an observation of doctrine. Obviously, Lutheranism is more complex than that as is demonstrated in the Confessio Augustana (Augsburg Confession) and the other symbolical documents of the Book of Concord. The structure of Lutheranism, thankfully so, is not bound to the personality of Luther (or it should not be). He was not the most personable fellow.
I have always found unusual the Lutheran critique of the polity of the Catholic Church. The Lutheran argument says that the structure of the Catholic Church, specifically the papacy, is de iure humano, that is, "of human right" as opposed to de iure divino ("of divine right"). This means that the polity of the Catholic Church is not of divine order but of human order. Meanwhile Lutherans gather in conventions or assemblies every few years to elect their leaders which they call their president. The process is very similar to the corresponding secular process as found in America. After this process, which includes no little amount of politicking, the president is chosen and this is understood and accepted as the work of the Holy Spirit. De iure humano or de iure divino? The Lutheran critique of the papacy is, in some ways, found wanting.
The largest and most liberal Lutheran group, the ELCA, has pretty much given up its polity to follow a template based on "the sexual revolution." Hence, like the rest of mainline protestantism, is quite comfortable with modern secular culture, including whatever sexual directions the culture is taking. The polity (and doctrine) of this declining group seem to go no further back in history than the 1960s (ie, "the sexual revolution"). Obviously, not all pastors and members are following this direction.
The largest conservative, or confessional Lutheran group, is the Missouri Synod. They are clearly distinct from the ELCA in doctrine and practice. The Missouri Synod is meeting this summer in convention and will be considering making major changes in polity through "restructuring", mainly in favor of providing more votes to larger congregations at the expense of smaller congregations (current practice is that each congregation has equal voice). There are many other proposals for changes. All in all, if passed, the Missouri Synod would be structured quite differently meaning, in practice, that its clearly stated doctrinal heritage would be permanently marginalized in favor of an amorphous "mission" (ie, evangelicalism).
Questions of polity are always questions of individuals and their relation to larger groups of people. Individuals, for example, are perturbed when larger groups or those who govern try to legislate their sentiment or tell them how they feel. There is room for mis-communication at all levels and in between levels of government. Those who govern, govern not only individuals but also organized groups of people. Mis-communication or misunderstanding does not necessitate change in structure. Polity is grounded in reason and law and not in sentiment. Sentiment, divorced from reason, can be a dangerous thing. Hence polity is needed for people to live together in a reasonable way.
As having served as a delegate at two conventions of the Missouri Synod I find them intriguing and frustrating. They are intriguing in the gathering of people from around the country and around the world and the dialogue over a variety of issues. They are frustrating in that what happens there is not always what one expects or desires. What will be both intriguing and frustrating to those who are at convention this summer is that they will be considering changing the very structure of the polity that has given them the opportunity to be there in the first place. For some, such changes would mean revoking their own future franchise. On a deeper level such changes would mean permanent change in the direction of the Missouri Synod, much of which would cut the synod from its roots.
On the other hand, cutting oneself from ones roots is a problem of the reformation. Ever since the reformation the countless denominations and sects, being rootless in terms of ministry, are continually forced to restructure or reinvent their polity. A denial of all that transpired in the Church between the time of the Apostles and the time of the reformation leaves protestantism always reacting and never learning, bound only to the last 500 or 50 years or 5 minutes of the Christian experience. One becomes bound by running from the past (ie, "your grandfather's church") and bound to novelty in all things. Evolution becomes the norm and protestantism becomes the religious sentiment of the secular culture. The lines are blurred between protestantism and the secular culture out of which develops a new civil religion. A Church without a polity of its own that can protect itself from the influences of secularism and speak clearly even when the culture objects is bound to forever reflect the polity and values of the culture, for better and for worse.
The life of people in the Church is first and foremost a gathering at the altar of the Holy Eucharist, a sort of heavenly polity. This polity reflects the mystery of the relationship that Christ has with His Bride, the Church (baptized believers). At the altar the crucified, risen and ascended Lord governs His people mercifully on earth, bringing peace between man and God, which was once and for all worked out on the cross and is now delivered to Christ's Bride. The incarnate Lord comes to us in His Body and Blood and sinners participate in the divine nature receiving a foretaste of the feast to come. In the desire for novelty many heirs of the reformation are losing what little is left that roots their life in the life of Christ and His Church, primarily the sacramental life, especially that given and received in the Holy Eucharist.
Related to the order of this life together is the Holy Ministry. In contrast to today's "small groups" (an evangelical phenomena) we find an apostolic ministry tied to Word and Sacraments, ordered and blessed by the Lord Himself. In today's rush to cut roots and forget the past and embrace whatever is new, many Lutherans may have forgotten or may have not even heard these words of the Augsburg Confession:
"Inasmuch as the Mass is such a giving of the sacrament, one common Mass is observed among us on every holy day, and on other days, if any desire the sacrament, it is also administered to those who ask for it. Nor is the custom new in the church . . . Chrysostom says that the priest stands daily at the altar, inviting some to Communion and keeping others away. And it appears from the ancient canons that some one person or other celebrated Mass and the rest of the presbyters and deacons received the body of the Lord from him, for the words of the Nicene canon read, 'In order, after the presbyters, let the deacons receive Holy Communion from the bishop or from a presbyter.'" (Augsburg Confession, Art. XXIV, Latin)
Polity is necessary for people to live together. The Lord provides a heavenly polity for people in the Church. In this polity, the center of the Church is found in the sacrament of the altar. On the one hand, for Lutherans, polity is "adiaphora." On the other hand, when we are enslaved by novelty we lose from the whole, many times, of that which we are not aware. And this brings disorder to our life together.
G.K. Chesterton said, "Once abolish the God, and the government becomes the God." Within the life of the Church, if the convention and all its activity replaces the life of Christ given in the Holy Eucharist then earthly government becomes the God. When the Holy Eucharist is set aside, re-structuring or not re-structuring makes little difference for earthly polity has little to do with heavenly polity and only lasts as long as the nation.