ZANESVILLE, Ohio — Sen. Barack Obama said Tuesday that if elected president he would expand the delivery of social services through churches and other religious organizations, vowing to achieve a goal he said President Bush had fallen short on during his two terms.

"The challenges we face today — from saving our planet to ending poverty — are simply too big for government to solve alone," Obama said, standing outside a community center in eastern Ohio. "We need an all-hands-on-deck approach."

Some Democrats have previously backed similar efforts, but Bush's version, a centerpiece of his first-term agenda, has been a lightning rod for criticism from those concerned about the separation of church and state and those who argued that Bush had used it to further a conservative political agenda.

In embracing the same general approach as Bush, Obama ran the political risk of alienating those of his supporters who would prefer that government keep its distance from religion.

But Obama's plan departed from the Bush administration's stance on one fundamental issue: whether religious organizations that get federal funds for social services can take faith into account in their hiring. Bush has said yes. Obama said no.

"If you get a federal grant, you can't use that grant money to proselytize to the people you help, and you can't discriminate against them — or against the people you hire — on the basis of their religion," Obama said. "Federal dollars that go directly to churches, temples, and mosques can only be used on secular programs."

Obama's position that religious organizations would not be able to consider religion in their hiring for such programs would constitute a deal-breaker for many evangelicals, said several evangelical leaders, who represent a political constituency Obama has been trying to court.

"For those of who us who believe in protecting the integrity of our religious institutions, this is a fundamental right," said Richard Cizik, vice president of governmental affairs for the National Association of Evangelicals. "He's rolling back the Bush protections. That's extremely disappointing."

Early in his first term, Bush issued a set of executive orders that expressly allowed faith-based organizations receiving federal money to consider religion in their employment decisions, although there remained much confusion about what is or is not permitted in this area because of conflicting federal, state and local laws.

Martha Minnow, a professor of law at Harvard University who has written about faith-based initiatives and has advised the Obama campaign on the issue, said Obama would move to "return the law to what it was before the current administration" — in other words, barring the consideration of religion in hiring decisions for such programs that receive federal financing.

"I don't think there's anything too controversial about that," she said. "Any religious organization that does not want to comply with that requirement simply doesn't have to take the money," she said.

But evangelical leaders said that not allowing religious groups to hire on the basis of their beliefs would strip them of the very basis for the faith-based programs.

"If you can't hire people within your faith community, than then you've lost the distinctive that is the reason why faith-based programs exist in the first place," said Richard Land, head of the public policy arm of the Southern Baptist Convention.

The idea of augmenting government delivery of social services through community and religious organizations has won varying degrees of support across the ideological spectrum and is part of a broader debate over how best to identify the most effective ways of addressing the causes of poverty and other social ills.

Obama's plan, which his campaign said would be the "moral center" of his administration — was unfurled against a backdrop freighted with electoral ramifications. Obama, who has demonstrated a facility in speaking about matters of faith, is signaling at this early stage of the campaign that he wants to make a push for support from white evangelical Protestants. That group made up about a quarter of the electorate in 2004 and voted for Bush over Sen. John Kerry by 78 percent to 21 percent.

By targeting centrist and more-liberal evangelicals, who have been pushing the movement to broaden its agenda beyond traditional social issues, Obama is hoping to chip away at a margin that has favored Republicans. His campaign decided to announce the plan in Ohio, a state where Bush engaged in a sprawling voter turnout effort among evangelicals.

Sen. John McCain, the presumptive Republican nominee, who has struggled to overcome wariness among some evangelicals to him, has been stepping up his outreach to evangelicals and is a proponent of faith-based initiatives as well. A McCain campaign spokesman, Brian Rogers, said McCain "disagrees with Sen. Obama that hiring at faith-based groups should be subject to government oversight."

Obama's proposal was met with praise from evangelical leaders like the Rev. Jim Wallis, who has become a prominent spokesman for more-progressive evangelicals. Wallis applauded the fact that Obama, as a Democrat, was willing to talk about his faith and "wants a faith-based program that's even better than the Bush program."

Several former Bush administration officials who had roles in crafting the current policy, including John DiIulio, who served as the director of Bush's office on faith-based initiatives in 2001, also applauded Obama's proposal. Though the program is widely associated with Bush, similar ideas have also been supported by Democrats.

"His plan reminds me of much that was best in both then-Vice President Al Gore's and then-Texas Gov. George W. Bush's respective first speeches on the subject in 1999," DiIulio said. "Especially in urban America, all the empirical evidence continues to show that local faith-based organizations can make a measurable civic difference."

But the Rev. Barry Lynn, executive director of Americans United for Separation of Church and State, criticized Obama's support of a program that he said has undermined civil liberties and civil rights. "I am disappointed that any presidential candidate would want to continue a failed policy of the Bush administration — it ought to be shut down, not continued," he said.

In one example of how he would use the approach to carry out a policy goal, Obama proposed $500 million a year to provide summer learning for 1 million poor children, with a goal of closing the achievement gaps between wealthy and poorer students. The campaign did not provide a cost proposal for the full program, but said the educational piece could be financed by reducing the growth in the federal travel budget and streamlining the management of surplus government property.

If elected, Obama said, he would call for a pre-inauguration review of all executive orders pertaining to the faith-based program, particularly those dealing with hiring practices. The program would "be central to our White House mission," he said, and would consider elevating the director of the Council for Faith-Based and Neighborhood Partnerships to a Cabinet-level post.

As he announced his proposal on Tuesday, standing outside the Eastside Community Ministry in Zanesville, Obama harked back to his early days as a community organizer in Chicago, where Catholic charities financed his programs.

"I didn't grow up in a particularly religious household, but my experience in Chicago showed me how faith and values could be an anchor in my life and an anchor in the community," Obama said, adding: "While I could sit in church and pray all I want, I wouldn't be fulfilling God's will unless I went out and did the Lord's work."

David Kuo, who served as deputy director of the White House Office of Faith-Based and Community Initiatives under Bush but eventually grew disenchanted and left, said the Obama plan seems to address some of the shortcomings with the Bush administration's efforts, making, for example, faith-based initiatives part of the domestic policy structure.

Kuo, who has criticized the Bush effort for getting bogged down in partisan politics, was asked by the Obama campaign to review its proposal. He expressed concern that Obama's plan would become mired in the dispute over the hiring issue, even though he said the issue, as a practical matter, affected very few organizations, but became a political football for interest groups on both sides.

"I think it is a bold, smart, engaging attempt to use religious organizations to help the poor and to do for the faith community what the Bush administration could not," Kuo said. "But I'm concerned that his position on hiring rights will bog down this initiative just like Bush's position on the other side did the same thing."