Welcome to the church-state battlefield, President Barack Obama. Consider this hypothetical landmine: Would it be discrimination for a Christian AIDS hospice to refuse to hire a worker who believes AIDS is a sign of God's wrath?

Ponder these scenarios. Can a Muslim school fire a teacher who converts to Christianity? Can a Jewish pre-school discriminate against a job applicant who is active in Jews for Jesus?

Wait, there's more. Is it job discrimination for an evangelical shelter for parents and children to refuse to hire someone who rejects centuries of Christian teachings on sex and marriage? How about forcing a Catholic hospital to hire doctors and nurses who reject the church's doctrines on abortion?

These are the kinds of questions swirling around the White House as Obama tries to find a way to embrace a wide variety of religious groups and the faith-based ministries they operate -- while rejecting some of the ancient doctrines that guide their work.

"There is no doubt that the very nature of faith means that some of our beliefs will never be the same," said Obama, at the National Prayer Breakfast in which he promoted his Office of Faith-Based and Community Initiatives. "We read from different texts. We follow different edicts. We subscribe to different accounts of how we came to be here and where we're going next -- and some subscribe to no faith at all.

"But no matter what we choose to believe, let us remember that there is no religion whose central tenet is hate. There is no God who condones taking the life of an innocent human being."

Then, citing a variety of faith traditions, he said one law can bring unity, which is "the Golden Rule -- the call to love one another; to understand one another; to treat with dignity and respect those with whom we share a brief moment on this Earth."

The audience said, "amen." But church-state lawyers and packs of social activists began murmuring about the details. There are, after all, secular and religious groups that believe President George W. Bush's team erred when it allowed many faith-based ministries to receive government funds, while hiring only employees who affirmed their doctrines and mission statements.

These tensions remain, because Obama has decided -- for now -- to allow this practice to continue, while stressing that the Justice Department will review complaints on a case-by-case basis.

The ground is moving. For decades, a guiding principle of church-state law has been that state officials must avoid becoming "entangled" in doctrinal questions that allow the government to favor some faith groups over others.

In his prayer breakfast speech, the president said his initiative would not "favor one religious group over another -- or even religious groups over secular groups." But will some ministries get to hire according to their doctrines, while others will not, with the government separating the sheep from the goats?

"I really don't have a clue" what the case-by-case language means, said Stanley Carlson-Thies, who worked with the Bush White House and now leads the Institutional Religious Freedom Alliance. "I think they are trying to get out of the fix they're in. Obama's people have told so many religious groups that they're not going to hurt what they do. Yet they have also told groups on the other side, 'Of course we stand with you. This is discrimination and we're not going to allow it.' "

As recently as the 1990s a broad coalition of church-state experts -- from the American Civil Liberties Union to the Christian Coalition -- managed to work together on some crucial religious liberty issues. The goal was to promote free speech, freedom of association and "equal access" for believers and nonbelievers in the public square.

But today, driven by conflicts over gay rights, the spotlight is on what candidate Obama consistently called "religious discrimination." The White House must choose between armies of religious believers who follow radically different sets of doctrines.

In the end, it's impossible to separate the power of faith from the doctrines and traditions that inspire these believers, said Carlson-Thies.

"The faith is where the passion comes from, it's where the witness is," he said. "It's clear that the president admires many of these faith groups and the work they do. The question he faces now is, 'Do you want to work with them or not?' "