WASHINGTON — While the U.S. Conference of Catholic Bishops has taken a cool response to many of President Obama’s policies, the one area where the two sides seem to be finding fragile common ground is on the need to reduce the number of abortions.

Just how to do that, however, has gotten tricky.

Obama and his Democratic allies on Capitol Hill say increased access to birth control and family planning will reduce the need for abortion by reducing the number of unplanned pregnancies. Catholic bishops, meanwhile, say artificial contraception is not only sinful but unreliable.

That’s put the U.S. church in an awkward political position: demanding an end to abortion, but being unwilling to support contraception, even as wide majorities of rank-and-file Catholics embrace it.

“I am not sure how the church can reconcile their two positions,” said Rep. Tim Ryan, an anti-abortion Ohio Democrat, and a Catholic, who has pushed abipartisan bill that would fight abortion by, among other things, increasing access to birth control.

“If we see a way to reduce the number of abortions through a common-sense, common-ground measure, we have an obligation to do it.”

The issue is gaining ground on Capitol Hill as House Democrats prepare a 2010 federal spending package that includes nearly $8 billion for pregnancy prevention and support programs. Catholic leaders say they can get behind abstinence-education funding, but little more.

“Abstinence prevents abortion; contraception does not,” said Marie T. Hilliard, director of bioethics and public policy for the Philadelphia-based National Catholic Bioethics Center.

Added Deirdre McQuade, a spokeswoman for the bishops’ pro-life office, “Contraception has never been shown to reduce abortion rates, so the assumption that it’s the heart of the answer is off base.”

If anything, the church hierarchy’s support for the contraceptive ban has become more entrenched. Pope Paul VI codified church teaching against contraception in 1968 in his encyclical, Humanae Vitae; it’s been defended by every pope since.

Pope John Paul II said the matter was closed and not up for discussion. Pope Benedict XVI, in marking the encyclical’s 40th anniversary last year, said “the truths laid out in Humanae Vitae have not changed.”

The president of the U.S. bishops, Chicago’s Cardinal Francis George, last year said the encyclical shows how “even under great societal pressures and hardships, the church will stand for moral truth in her teachings and remain strong regardless of the consequences.”

The problem for the bishops has been twofold.

For one, the bishops have been isolated on the contraception issue, including from other religious groups who share the bishops’ opposition to abortion, but especially from their own flocks. Sixty-one percent of U.S. Catholics insist that individuals should have the final say on contraception; 75 percent say it’s possible to be a good Catholic while disobeying church teachings on the matter, according to recent surveys.

“Catholics are like everybody else,” said Jon O’Brien, president of the group Catholics for Choice, which supports both abortion rights and access to contraception.

“We want to have a caring, loving family and we know that contraception makes total sense. That’s why we use it. Contraception matters. Banning it makes married life pretty miserable for a lot of people.”

The larger challenge has come from lawmakers, especially Catholic Democrats like Ryan, and a White House that is adept at using religious rhetoric to appeal for a middle ground that the bishops seem unwilling or unable to provide.

In announcing the $8 billion for abortion prevention, House Appropriations Committee Chairman David Obey, a Catholic Democrat from Wisconsin, slapped the words of Jesus himself — “… whatever you did for one of the least of these brothers of mine, you did for me” — across the top of his press release.

The Rev. Thomas Reese, senior fellow at the Woodstock Theological Center at Georgetown University, said American Catholics’ rebellion on contraception has made it harder for the bishops to present a unified front in trying to shape legislation on Capitol Hill.

“They’ll support any amendment that strikes (contraception) from the bill, but my guess is that they won’t have the votes to make it happen simply because not even Catholics agree with them on birth control, let alone the rest of the country,” Reese said.

The White House has made abortion reduction one of the four focus areas of its revamped Office of Faith-based and Neighborhood Partnerships. It’s not clear yet what abortion-reduction policies that office will recommend, but they are widely expected to include expanded access to contraceptives.

So is there a way for the bishops to work with a Democratic Congress and a Democratic White House to reduce abortions without endorsing contraception? Cristina Page, author and moderator of the online forum “On Common Ground,” said abstinence should be stressed as the first and strongest message young Catholics learn, but it cannot stop there.

“A more comprehensive sexual education should emphasize abstinence, but it should be coupled with information about contraception,” she said.

Reese said an abstinence-only culture is a nice idea, but even the bishops know there are limits to its appeal or effectiveness. After all, the bishops themselves said in 2006 that just 4 percent of married Catholics embrace church teaching on “natural family planning.”

“The opinion polls are quite clear,” he said. “The bishops will continue to teach what they believe is proper moral teaching, but they’re not fools. They know what the people in the pews are doing and thinking.”