I've heard it said that one of the paradoxes of the Christian church is that the larger and more successful it becomes, the more it loses its true power. The more influence Christians gain in the world around them, the more they seek to wield their newfound power at the expense of the self-sacrificial love that first drew them to the faith.
It seems odd to suggest that the church might be losing its power; after all, the evangelical church is arguably more influential than ever, at least in the United States. But with that political power has come a reputation for nastiness and self-righteousness that has soured many people on Christianity and on organized religion in general. Most of the evangelical church's growth in recent years has come at the expense of mainline Christian denominations, however; those leaving the church altogether in most recent years outnumber the new converts coming in.
It's a cycle that's been paralleled more than once in church history. At the beginning the church was a tight-knit community, a tiny outgrowth of Judaism that might well have stayed small and eventually died out. It had the power to transform lives, however; those on the outside saw the love that these Christians had for one another and for others, and the church's message quickly began to spread across the Roman Empire.
With the introduction of Gentiles into the faith, the church's leaders faced a dilemma. They opted not to place these new converts under the burdensome requirements of the Jewish law, but felt that some standards were necessary lest the term 'Christian' cease to have any meaningful definition. Those standards started out simply enough; a few general admonitions accompanied by a short list of specific commands was all that anyone needed. Believers were united by their faith in Christ and their commitment to loving God and each other.
Over time, though, that list gradually grew longer as subsequent generations felt it necessary to require conformity of belief and behavior on the church's diverse membership. Soon church councils were being formed to agree on basic doctrines, with those deemed heretics expelled from Christendom entirely. The church as a whole continued to prosper, as it was still largely demonstrating love of a sort seldom seen elsewhere in the world, but doctrinal and personal purity were gradually replacing compassion as the church's primary distinction.
As the church expanded further, it eventually became a political power with influence over laws and other matters of public policy. Long gone was the humility that early Christians had demonstrated in all of their dealings; believers now knew what was best for everybody, and they had the power to force others to accede to their convictions. The Bible was now a rulebook, its narratives, poems, parables and conversations reduced to a patchwork quilt of detailed instructions for regulating every aspect of life.
The Holy Spirit was no longer seen as sufficient to the task of guiding individual believers or bringing the wayward to faith; failure to conform to the church's ever-lengthening list of doctrines and rules was viewed as evidence that an individual was rebelling against the Spirit and in need of disciplining. Soon heretics and pagans were being executed and those that violated "God's moral law" were subject to punishment by civil authorities.
Although some individuals remained committed to the path of self-sacrificial love, their quiet example was largely drowned out by the din of those whose concept of love had taken the form of a stern parent tasked with scolding and disciplining her wayward children. The church's reputation became every bit as ugly as that of the heathen rulers it had supplanted - worse, even, since its depredations were carried out in the name of a supposedly loving God.
Over time the church's influence gradually waned, but not before events like the Crusades, the Inquisition and any number of witch hunts became permanently ingrained in the public consciousness as examples of the dangers of organized religion in general and of Christianity in particular.
That's an oversimplified summary of church history, but hopefully it serves to clarify the correlation that some have observed - namely, that the church can only increase its political authority at the expense of its spiritual power. Coercive power is a corrupting force, and even the purest of heart can't wield it for long and come away untainted.
A growing number of evangelicals are starting to recognize just how badly the religious right's various crusades have blackened their reputation over the last 20-30 years and are beginning to back away from political activism as a result. Whether they'll also take a step back from the legalism that creates such a strong temptation to strive for political power remains to be seen.
"It's a relationship, not a religion" is a popular catchphrase among evangelicals. It's also a slogan that rings hollow when that "relationship" turns out to be defined primarily by the substitution of one set of rules for another. As long as conformity is a requirement for inclusion, it is indeed a religion and not a relationship.