Space does not permit me to give you a history of the use of the word "evangelical" in organized religion. Suffice to say, it evolved after its earliest years into a movement that carried a zeal and missionary spirit for the Protestant denominations that proudly put the word into their name [i.e. Evangelical Lutheran Church]. It evolved as a mainstream term used in mainstream Protestantism. In the U.S. it has been usurped by out-of-the mainstream church groups. I can't call them "denominations" because they fit more closely to the individual parish pastor's flavor of showmanship than to a set of beliefs, doctrines, and rubrics established by a national or international church body.
Oh, how angry some "evangelicals" will be for me to frame them that way. But it is basically true, in a summarized version. What today we call mega-churches are beholden to a local group of pastors and members who have rallied around the dynamic of what passes for worship. Some are very good, some are akin to a Disney movie. In recent decades these non-denominational mega-churches and mega-church-wannabes have tried to precipitate out some semblance of theological order and principles that serve people outside the walls of the pretty church auditoriums. They were open to criticism for their showmanship that lacked basic tenets or theological scholarship.
These mega-churches found a cohesive way to tie together a semblance of biblical and/or theological unity. They found it in politics. The leaders were often TV darlings with quasi-credentials in Christian teaching. Politicians were easy targets who could not truly fight back at outlandish and ultra-dramatic charges. They usurped causes like right-to-life, the right to own a gun, etc. There was little in their litany for service to the poor and minorities. Huge fortunes were built by these early "evangelical" TV darlings. Pounding their chests against the sin of liberals and progressives, some of them got caught up in their own personal transgressions. Jimmy Swaggart and Jim Baker come quickly to mind. But there were many, many others. They have learned from these mistakes and now play their personal lives as though their fortune depended upon it; and it does. And they have become very selective in which politicians they single out. Bill Clinton and John Edwards are horrible sinners, Newt Gingrich's similar escapades are forgiven.
Perhaps the most tragic development in the evolution of these so-called evangelical churches is that they greatly helped George W. Bush get elected twice to the White House. And you realize what that has meant. They can muster their troops to fight the terrible demons that surround us. But the material riches of these individual churches do not find real service to minorities, the poor, the needy, the underserved in our society; it is peanuts compared to what is done by much tinier churches in mainstream Christianity. Oh, the numbers look big, but the per capita is atrocious by comparison. Realizing that they may be on the brink of the larger society putting them under the microscope and calling their bluff, they are now on a PR campaign to look more sensitive to the needs of people outside their shallow purview.
However underlying any real scrutiny of their "mission," is the threat that they can destroy you with their self-righteous clout. They can organize in a second to parade against abortion, but have very little to give in serving the unwanted children that surround all of us. This is a real tragedy, Christian or otherwise.