One moment defined old-school evangelicalism more than any other -- the altar-call ritual in which the Rev. Billy Graham urged sinners to come forward and repent, accept God's forgiveness and be born again. 

For decades, crusade choirs sang "Just As I Am," which proclaims: "Just as I am, and waiting not to rid my soul of one dark blot, to thee, whose blood can cleanse each spot, O Lamb of God, I come, I come." 

So evangelical activist Tony Campolo knew he was grabbing heartstrings as he referenced this gospel hymn when announcing that he had changed his beliefs on marriage and homosexuality. 

"As a social scientist, I have concluded that sexual orientation is almost never a choice," said the 80-year-old Campolo, for decades an influential voice on Christian campuses. "As a Christian, my responsibility is not to condemn or reject gay people, but rather to love and embrace them, and to endeavor to draw them into the fellowship of the Church. 

"When we sing the old invitation hymn, 'Just As I Am,' I want us to mean it." 

With this nod, Campolo underlined crucial questions in heated debates linked to the emerging evangelical left: Since the movement called "evangelicalism" lacks a common structure and hierarchy, who decides what the Bible says about repentance and forgiveness? Who decides when acts cease being sinful and become blessed?            

For example, "Just As I Am" has always called sinners to seek forgiveness, stressed Mark Tooley, president of the Institute of Religion and Democracy. Now, Campolo has interpreted it as an "affirmation of the moral status quo" -- omitting a call for repentance, since he has evolved on key moral doctrines. 

Tooley and other critics have noted Campolo's affirmation that he remains a "staunch evangelical" who salutes the "doctrines of the Apostles Creed," while believing the Bible's authors were "inspired and guided by the Holy Spirit." However, Campolo also said, "people of good will can and do read the scriptures very differently when it comes to controversial issues." 

"Whatever he says about the Bible, what Campolo has done is change his stance on the issue that is the flashpoint between faith and culture in our age," which is whether sex outside of marriage is sin, stressed Tooley, an evangelical in the United Methodist Church. "This has been the crucial issue on the Protestant left for some time now -- at least among many Protestants in America, Europe and churches in the West. … We are now seeing a strong effort to pull this debate inside the world of evangelicalism." 

Campolo's shift was not shocking. He has, for decades, been one of the leaders most likely to appear in lists of self-avowed evangelicals backing Democratic presidents in fights with religious conservatives. The surprise was when his decision drew praise from David Neff, who from 1993 to 2012 was editor of Christianity Today, founded in 1956 by Graham and theologian Carl F.H. Henry. 

In Facebook statements, Neff first said: "God bless Tony Campolo. He is acting in good faith and is, I think, on the right track." Later, he confirmed his doctrinal shift in an exchange with a Christianity Today writer: "I have come to read the relevant passages differently … and have come along a similar path" as Campolo. 

Christianity Today immediately responded with an editorial -- "Breaking News: 2 Billion Christians Believe in Traditional Marriage" -- by current editor Mark Galli. 

The church, he argued, "remains overwhelmingly united" around a core theology "assumed or articulated by the great theologians and Christian philosophers in the Protestant, Orthodox, and Catholic traditions -- the most sophisticated recent effort being John Paul II's work on the theology of the body. … It is not driven by an irrational prejudice of people living in the past, as the American zeitgeist assumes." 

 It's significant, noted Tooley, that this flagship evangelical magazine appealed to traditions in ancient, global churches -- Roman Catholicism and Eastern Orthodoxy -- during this debate inside contemporary evangelicalism about how to read the Bible. 

On the other side are progressives who have "come out of mainstream evangelical culture and are now trying to modernize the doctrines of their old churches and schools and organizations," he said. "It's all pretty confusing, but one thing is clear: The world of liberal Protestantism now has an evangelical wing."