DENVER, (By David D. Kirkpatrick and Laurie Goodstein, NYTimes) October 9, 2004 - For Archbishop Charles J. Chaput, the highest-ranking Roman Catholic prelate in Colorado, there is only one way for a faithful Catholic to vote in this presidential election, for President Bush and against Senator John Kerry.

"The church says abortion is a foundational issue,'' the archbishop explained to a group of Catholic college students gathered in a sports bar here in this swing state on Friday night. He stopped short of telling them whom to vote for, but he reminded them of Mr. Kerry's support for abortion rights. And he pointed out the potential impact his re-election could have on Roe v. Wade.

"Supreme Court cases can be overturned, right?" he asked.

Archbishop Chaput, who has never explicitly endorsed a candidate, is part of a group of bishops intent on throwing the weight of the church into the elections.

Galvanized by battles against same-sex marriage and stem cell research and alarmed at the prospect of a President Kerry - who is Catholic but supports abortion rights - these bishops and like-minded Catholic groups are blanketing churches with guides identifying abortion, gay marriage and the stem cell debate as among a handful of "non-negotiable issues."

To the dismay of liberal Catholics and some other bishops, traditional church concerns about the death penalty or war are often not mentioned.

Archbishop Chaput has discussed Catholic priorities in the election in 14 of his 28 columns in the free diocesan newspaper this year. His archdiocese has organized voter registration drives in more than 40 of the largest parishes in the state and sent voter guides to churches around the state. Many have committees to help turn out voters and are distributing applications for absentee ballots.

In an interview in his residence here, Archbishop Chaput said a vote for a candidate like Mr. Kerry who supports abortion rights or embryonic stem cell research would be a sin that must be confessed before receiving Communion.

"If you vote this way, are you cooperating in evil?" he asked. "And if you know you are cooperating in evil, should you go to confession? The answer is yes."

The efforts of Archbishop Chaput and his allies are converging with a concerted drive for conservative Catholic voters by the Bush campaign. It has spent four years cultivating Catholic leaders, organizing more than 50,000 volunteers and hiring a corps of paid staff members to increase Catholic turnout. The campaign is pushing to break the traditional allegiance of Catholic voters to the Democratic Party, an affiliation that began to crumble with Ronald Reagan 24 years ago.

Catholics make up about a quarter of the electorate, and many conservative Catholics are concentrated in swing states, pollsters say. Conservatives organizers say they are working hard because the next president is quite likely to name at least one new Supreme Court justice.

Catholic prelates have publicly clashed with Catholic Democrats like former Gov. Mario M. Cuomo of New York and Geraldine A. Ferraro, the former representative and vice-presidential candidate.

But never before have so many bishops so explicitly warned Catholics so close to an election that to vote a certain way was to commit a sin.

Less than two weeks ago, Archbishop Raymond L. Burke of St. Louis issued just such a statement. Bishop Michael J. Sheridan of Colorado Springs and Archbishop John J. Myers of Newark have both recently declared that the obligation to oppose abortion outweighs any other issue.

In theological terms, these bishops and the voter guides argue that abortion and the destruction of embryos are categorically wrong under church doctrine. War and even the death penalty can in certain circumstances be justified.

But it is impossible to know how many bishops share this view, and there is resistance from a sizable wing of the church that argues that voting solely on abortion slights Catholic teaching on a range of other issues, including war, poverty, the environment and immigration.

Liberal Catholics contend that the church has traditionally left weighing the issues to the individual conscience. Late in the campaign, these Catholics have begun to mount a counterattack, belatedly and with far fewer resources.

In diocesan newspapers in Ohio, Pennsylvania and West Virginia, they are buying advertisements with the slogan "Life Does Not End at Birth." Organizers of the campaign say it is supported by 200 Catholic organizations, among them orders of nuns and brothers.

"We are looking at a broader picture, a more global picture," said Bishop Gabino Zavala, an auxiliary bishop of Los Angeles who is president of Pax Christi USA, a Catholic peace group that initiated the statement. "If you look at the totality of issues as a matter of conscience, someone could come to the decision to vote for either candidate."

In the presidential debate on Friday, Mr. Kerry discussed his religious beliefs. "I was an altar boy," he said. "But I can't take what is an article of faith for me and legislate it for someone who doesn't share that article of faith, whether they be agnostic, atheist, Jew, Protestant, whatever."

Alexia Kelley, director for religious outreach for the Democratic National Committee, said Mr. Kerry's policies reflected overall Catholic teachings.

The Republican Party is betting that many observant Catholics will disagree. The National Catholic Reporter reported that that on a visit to the pope this year Mr. Bush asked Vatican officials directly for help in lining up American bishops in support of conservative cultural issues.

For four years, the party has held weekly conference calls with a representative of the White House for prominent Catholic conservatives. To ramp up the Catholic campaign last summer, the party dispatched its chairman, Ed Gillespie, and a roster well-known Catholic Republicans on a speaking tour to Catholic groups throughout the swing states.

The party has recruited an undisclosed number of Catholic field coordinators who earn $2,500 a month, along with up to $500 a month for expenses to increase conservative Catholic turnout.

In an interview this week from Albuquerque, where he was rallying Catholic outreach workers, Leonard A. Leo, executive vice president of the Federalist Society, a conservative legal group, who has taken the role of informal adviser to Mr. Bush's campaign on Catholic issues, said Republicans hoped that Mr. Bush could draw even more of the Catholic vote than Reagan, who attracted 54 percent when he ran for re-election in 1984. Mr. Bush received just under half of the Catholic vote in 2000. In a Pew Research poll this month, 42 percent of white Catholics favored Mr. Bush, 29 percent favored Mr. Kerry, and 27 percent were undecided.

"I can't think of another time in recent political history where a political party and a campaign have paid more attention to faithful Catholics," Mr. Leo said.

How the bishops' guidance or the new voter guides are playing in the pews remains to be seen. In a poll for Time magazine in June, 76 percent of Catholics said the church's position on abortion made no difference in their decisions about voting. But in a New York Times poll conducted over the summer, 71 percent of Catholics favored some restrictions on abortion, compared with 64 percent of the general public.

Republican strategists say Catholics and others who attend religious services at least once a week tend to be more conservative. Fifty-three percent of those Catholics supported Mr. Bush in 2000 compared with 47 percent of all Catholics, according to exit polls. The Rev. Frank Pavone, national director of Priests for Life of Staten Island, N.Y., says priests with his group are going from church to church in swing states like Florida, giving fellow priests sample homilies for each Sunday in November, inserts for church bulletins and voter guides.

Father Pavone spoke by telephone from Aberdeen, S.D., where he said he was meeting with dozens of priests and nuns to teach them how to organize transportation to take parishioners to the polls. Addressing abortion, he said he told audiences, "One can't hold public office and say it's O.K. to kill some of the public."

In past elections, the main voter guide distributed in many Catholic churches was a questionnaire from the United States Conference of Catholic Bishops that listed candidates' stands on dozens of issues. This year, conservative Catholic groups sought to derail the questionnaire, because it appeared to give equal weight to each issue. When neither the Bush nor Kerry campaigns responded to the questions by the deadline, the bishops' conference abandoned the effort, a spokesman, Msgr. Francis Maniscalco, said.

Many parishes are having free-for-alls over what materials to use in helping Catholics think through their choices. Many bishops are using a document the bishops developed last year, "Faithful Citizenship." It tells Catholic voters to consider a range of issues and vote their consciences. Other parishes are instead using a guide from a conservative Web site, Catholic Answers, at www.catholic .com. The guide says it is a sin to vote for a candidate who supports any one of five "non-negotiable issues," abortion, euthanasia, embryonic stem cell research, human cloning and homosexual marriage.

Archbishop Chaput says he has had no contact with either campaign or political party. He says his sole contact with the White House has been his appointment to the United States Commission on International Religious Freedom. The prelate acknowledged that his communications director, Sergio Gutierrez, had worked in the Bush administration, but Archbishop Chaput said he had known Mr. Gutierrez long before that.

It was only logical for the Republicans to view the church as a "natural ally" on cultural issues, the archbishop said. He said that would end if a Republican candidate supported abortion rights.

"We are not with the Republican Party," he said. "They are with us."

Mr. Kerry's Catholicism is a special issue for the church, Archbishop Chaput said. To remain silent while a President Kerry supported stem cell research would seem cowardly, he said. The Rev. Andrew Kemberling, pastor of St. Thomas More Church near here, said he agreed with the archbishop, but he acknowledged that parishioners sometimes accused him of telling them how to vote. He said his reply was: "We are not telling them how to vote. We are telling them how to take Communion in good conscience."