It is useful to understand that, in the US, the decentralization of Christian power in the post-Reformation era produced a hundred or more small centers of organization - the denominations; each of which reflect the era in which they crystallized; the cultural heritage of the ethnic group to which the originators of the denomination belonged, and the peculiarities of the personalities who formed the ideas and traditions that constitute the crystalline structure in consciousness that is copied by its adherents from generation to generation.
It is as if, when the originating organism - the Roman Catholic Church, broke into pieces, each broken piece grew anew, but with only fragments of the code of the parent organism, and incorporating new instructions from elements that it synthesized from competing and proximal religious systems; and from mutations that were introduced by individuals and smaller collections as they replicated; so that, decade by decade, an entirely diverse set of child organisms, like so many breeds of dogs, appeared - all of them still called Christian.
Everyone knows how broken up Christianity is - but in the common vernacular, because that common vernacular is secular in character, and the conflict between religious factions in the US has been minimized and detoxified by the overriding principle of the separation of church and state, it is not typical to ever hear in the common media anything but generalities and an assumed Christian identity - the American identity which is generalized as 'Christian' subsumes denominational identity in the media as it does in public schools or the military where identity rooted in Christian factionalism has historically been, in essence, rendered invisible. There are few exceptions that are most-often labeled as cults, very few of which are explicitly not Christian; and then there are growing populations of non-Christian religions - but these are not the main subject of this post.
The fight over gay marriage exposes the factionalism that still characterizes Christian denominations, even splitting some yet again as members resist giving up the copy that they personally have preserved - as older folks have resisted giving up 19th century hymns. There are numerous Baptist groups, many Lutheran groups, a few variations of the Church of Christ (my favorite being the Church of Christ Non-Instrumental: they do not use musical instruments...)
In rural areas, Christianity is largely a copy of the culture as it was in the colonial era or the era of mass in-migration from 19th century Europe. In the suburbs, Christianity has synthesized mass culture syncretically, so that the guitar and the hippie culture appear on the stage of the church-as-theatre along with a traditionally dressed minister; and more, the suit and tie have disappeared along with Thee and Thy. In the major cities, the historic edifices of the Protestant High Churches stand all around, and only recently have been re-incorporated as lively centers of activity - their blue-haired decades almost at an end.
In the latter half of the twentieth century, we could classify Christianity in the US has having five major groupings: Ecumenists - secularized Christians in urban areas who wished to preserve the experience of churchgoing and its formal buildings, music, and traditions; Fundamentalists - factions of Christians whose core identity hardened around the middle of the 19th century when biblical literalism sought to counter science, as religion fought with science for legitimacy. Ironically, biblical literalists seized on the Bible as empirical evidence of God's existence and instruction manual; Pentecostals - Christians who have incorporated ecstatic personal experience, experience of the Holy Spirit, and formalized it alongside with a variation of fundamentalism; Mega-church Christians - Christians whose identity is a blend of all-of-the-above - suburban Christianity, and lastly Roman Catholics - who are a mix of Ecumenists and Fundamentalism - but a fundamentalism based on traditions and not on literal interpretations of the Bible.
Ecumenists are gay welcoming. In the urban churches that are the base of the ecumenist movement and in their partner churches even in places like Arkansas, where the message of ecumenism, however isolated in its minority status, is essentially urban in character, Ecumenists have created a comfortable synthesis of science and religion, preserved their fine buildings, created a community of friends, and are the inheritors of the 18th and 19th century Christian enlightenment philosophies of liberalism and positivism.
Fundamentalists are gay fearing if not always gay hating. The central idea of fundamentalism is heaven versus hell, God versus the Devil; and in this intensely dualistic and confused Christianity, projection is the main psychological mechanism. To fundamentalists anything other than the copy they themselves made of the religion they inherited is likely to be evil. Fundamentalists are the culture war. Because their knowledge of God is equal to the force of their ability to interpret His Word - they are easily led by those that lay claim to the best interpretation, and because Fundamentalism cannot stand up to even a basic education - they are constantly in conflict with the culture around them, and are only comfortable in communities that are not intellectually or culturally diverse.
Pentecostals are gay-fearing and anti-gay on account of their also being Fundamentalists of a kind, and because the way in which they have formalized religious ecstasy (glossolalia - speaking in tongues, their music and their ideology is too narrowly defined and too much a copy of the 19th century encounter between Christianity and African ecstatic religions to incorporate gay identity, which itself is a political construction formed out of modern urban conditions and is alien to the pre-WWII culture that Pentecostalism preserves.
Mega-church Christianity is up for grabs for gays. A mix of watered down Fundamentalism and Pentecostalism, mega-church Christianity reflects the intrusion and incorporation of modern media into religious practice - from Kathryn Kuhlman and Oral Roberts to Billy Graham and the Jesus Movement, celebrity pastors lead large and essentially temporary congregations through increasingly sophisticated adaptations of the mass secular culture's music. Mega-church Christianity is a form of consumer culture - the congregation as audience and the church as theater. At the core of mega-church Christianity there remains its major problem - whether the Bible is empirical evidence of God - and thus God's rulebook - or whether God must be experienced existentially - Jesus as personal savior. So far, Mega-churches continue to lean to the direction of God and/or Jesus as Judge and Prosecutor (God retaining the role as sentencer and Jesus as Intercessor , Pastor as Lawyer, and the Bible as law. but they are moving steadily in the direction of the church as a social club whose primary goal is to fill the gap in people's lives for a sense of community, however ad hoc. More than 40% of attendees to California's mega-churches voted to keep gay marriage legal. They almost all have gay friends or family.
For gay identity - the fight for equality depends on insinuating copies of gay identity into these major Christian categories, or defeating the principles around which they are organized, as Luther and the Reformation leaders defeated the bishops who dominated the longest lasting copy - the Roman Catholic church. This is why it makes sense to single out Mormons, who claim to be Christians, but whose claim is largely rejected by the remainder of Christian types. They are already weakened by the perception of Fundamentalists and Pentecostals and Roman Catholics that Mormonism is a heretical cult.
Fundamentalists inherently cannot accept insinuation of gay identity into their community - they are an enemy of gay identity and can only be weakened by reduction of their number; and reduction of their number can only be accomplished one-on-one by persistent rational argument on their turf - the turf of the Bible; and in the general public, by isolating them through ridicule and ostracizing - because their ideas are without merit or sense and reasonable people should reject their ideas with force and vigor.
Pentecostals are perhaps today the most virulently anti-gay - but because their religious views are based on religious ecstasy and personal experience - they can be picked off one by one or by competing on their turf - which is powerful religious experiences, but as an institution they must be defeated, as with fundamentalists. If they see that someone is having a more powerful and exciting religious experience than their own - they often drop their fundamentalism and move on - it is a relatively fluid population. For blacks, in some measure, hip-hop is such a competing culture: while it is not religious in character, it is identity-creating and offers an alternative to gospel, as rock'n'roll offers an alternative to the moribund culture of religious hymnody and the neo-classicism that characterizes the mainstream religions. Since Pentecostal ideas and practices are anachronistic in the context of American secular culture - their influence among the middle and upper classes will continue to wane; but in the Third World and among the black communities of the US it is a different story - there, Pentecostals and their kissing cousins, black churches with gospel music or full gospel churches - have as their core identity a powerfully preserved and defended religious identity - an identity that formed in the context of slavery and thus is hardened as a diamond against outside influence. Pentecostalism in Latin America has shown remarkable growth in every urban area. American and South American black Pentecostalism are both a synthesis of African ecstatic and spiritist practice (the Holy Ghost is very African!), poor white fundamentalist, and traditional Pentecostal elements. Black religion is intensely internalized and resistant to change, and it is anti-gay: just as anti-gay as the black community generally - because at its core, for African-Americans, be they South or North American, gay identity is an alien and deviant outgrowth of white culture and a threat to black masculinity. Black religion and black culture will not change as long as black men are on the down low - and can only be changed by insinuating masculine gay personalities into the pantheon of personalities that African-American peoples choose to replicate in their own person: it cannot be defeated by white intellectuals, rational arguments, or the success of white persons.
Because Americans consider themselves to be members of a Christian nation, and because Christianity historically has been homophobic in the extreme, I am generally Anti-Christian. Having worked in Washington DC for the last year +, I have come to understand that the Ecumenists are genuinely accepting and warmly embrace homosexual persons and gay identity. The large urban churches in DC fly rainbow flags, proudly include the code words 'welcoming' and 'open and affirming' to announce their acceptance and even proselytizing of gay men and women. Even the mainstream Riverside Baptist church actively solicits gay membership - something I shared with my father, who spent 27 years as a fundamentalist Baptist preacher, but is now alienated from that tradition and essentially is not tied to any denomination.
The evolution of Christianity in this country points to a time in the next generation (well, for this generation, depending on how old you are...) when fundamentalists and Pentecostals will form a tiny minority of the overall religious community, and while African-Americans are likely to lag, since most African-American congregations are one form or another of fundamentalist/pentecostal - it is possible that leadership in the form of breakthrough individuals will create new models that people will use to clone personal identity as they form or re-form their own personality. Ecumenists are already welcoming, and mega-church Christians are so much a copy of secular culture that the time is very near that the issue of homosexual persons and gay identity will be a thing of the past, like divorce, female independence, and other issues before it.
This generational shift is the gay community's chance to accelerate that process by insuating its presence in the ranks of those Christian groups that accept them, and by openly working to defeat those that do not by attacking the weak foundation upon which their ideology and practice rests.