(Adds quotes, background)

By Ed Stoddard

GRANTHAM, Pa., April 13 (Reuters) - Democratic presidential candidate Hillary Clinton defended her support for abortion rights at a faith forum on Sunday, saying the decision to have an abortion was not just about the "potential life" of a child, but the lives of others involved, including the parents.

Clinton and her rival for the Democratic presidential nomination, Barack Obama, attended the event sponsored by Faith in Public Life, a nonpartisan resource center. The Democratic candidates were courting religious activists from across the political spectrum -- a group with clout in U.S. politics.

Abortion is one of the most divisive issues in American politics and many of the evangelical Christian leaders and others in the audience were opposed to abortion rights for religious reasons.

Clinton was pointedly asked during the nationally broadcast forum if she believed life "begins at conception."

"I believe that the potential for life begins at conception ... but for me, it is not only about the potential life, but the other lives involved," Clinton said, noting her Methodist faith and the denomination's own struggle with the issue.

She also reiterated her belief that while abortion should remain legal, it should also be safe and rare.

"Individuals must be entrusted to make this profound decision because the alternative would be such an intrusion of government authority that it would be very difficult to sustain in our open society," she said at the forum held on the campus of Messiah College near Harrisburg, Pennsylvania.

Obama, whose time on the show followed Clinton's, said "adoption is an option," but stressed that he remained committed to the support of abortion rights.

Also asked if he thought life began at conception, Obama said: "This is something that I have not, I think, come to a firm resolution on. ... I don't presume to know the answer to that question."

The candidates were also asked questions about issues including poverty, human rights and climate change -- issues which have been embraced by the powerful U.S. evangelical movement as it broadens its agenda beyond hot button social issues such as opposition to abortion rights and gay marriage.

"We are going to put in place a cap-and-trade system that controls the amount of greenhouse gases that are going into the atmosphere. ... I think religion can actually bolster our desire to make those sacrifices now," Obama said.

Clinton evoked Christ to explain her concern for the poor.

" ... The incredible demands ... that Christ called us to respond to on behalf of the poor are unavoidable," she said.

The forum was held about a week before Pennsylvania's Democratic primary election, which the Obama camp hopes will clinch the hard-fought contest to pick the party's candidate to run in November's presidential election.

Presumptive Republican presidential nominee John McCain declined an invitation to the forum, raising eyebrows in the evangelical community.

McCain's Republican Party has been much more closely associated with the "faith vote," especially evangelicals. In the 2004 election President George W. Bush got close to 80 percent of the support from white evangelical Protestants who cast ballots in that year's White House election.

But McCain has been uncomfortable talking about his faith -- in marked contrast to Clinton and Obama -- and many conservative Christians have not warmed to him because of his support for stem cell research and other political heresays.

"It's a missed opportunity for him (McCain). You don't get opportunities like this very often and anywhere from 25 to 40 percent of the evangelical vote is up for grabs this year," said Richard Cizik, vice president for governmental affair at the National Association of Evangelicals.

"This vote is up for grabs for a number of reasons, including the broadening of the evangelical agenda," he told Reuters on Sunday ahead of the forum.

AlertNet news is provided by