Opponents of the death penalty are targeting the anti-abortion movement as a potential ally.

Led by David Kaczynski, whose brother – the Unabomber – is now serving a life sentence, the group New Yorkers Against the Death Penalty has launched an effort to lure anti-abortion Catholics to its cause, citing a common interest in advancing a “culture of life.”

The group is trying to build on momentum gained since June 2004, when the state’s highest court struck down a 1995 law restoring the death penalty. An Assembly bill revising the statute died in committee earlier this year, but death penalty opponents have not declared victory, pointing to the possibility of future legislation.

By setting its sights on Catholics, New Yorkers Against the Death Penalty is looking to promote the message that a “culture of life” should signal more than an opposition to abortion.

“When Pope John Paul II coined the phrase ‘culture of life,’ he was referring to a whole range of issues, including opposition to the death penalty,” said Mr. Kaczynski, the group’s executive director, who gained fame in 1996 when he helped federal authorities catch his brother, Theodore Kaczynski.

The group held a forum at St. Matthias Church in Queens on Monday. It says it will continue its campaign in advance of an expected vote in November by the U.S. Conference of Catholic Bishops on a resolution opposing the death penalty.

Mr. Kaczynski has allies in the church, including Bishop Howard Hubbard of the Albany archdiocese, but his supporters concede that it can be a challenge to link two issues on which views can be deeply entrenched.

“It’s an uphill battle,” the director of pro-life activities for the New York State Catholic Conference, Kathleen Gallagher, said. “I think we need patience and perseverance on both sides.”

In a March poll by Siena College, 46% of New Yorkers said they opposed reinstating the death penalty in New York, while 42% favored it.

While opponents cite moral objections, supporters contend capital punishment has value to law enforcement and call it an appropriate punishment for the most heinous crimes. “I think that it’s a certain deterrent,” the state Assembly minority leader, Charles Nesbitt, said. “We need it as part of our arsenal.”

Mr. Nesbitt, a Republican, said he wanted to see the issue come before the Legislature again, after a committee vote in April blocked a bill restoring the death penalty from a full floor vote.

In taking his death-penalty battle to city churches, Mr. Kaczynski has enlisted Antoinette Bosco, a Catholic writer who has spoken out against the death penalty since her son and his wife were murdered in their Montana home in August 1993.

The brother of a killer and the mother of a victim may make an odd couple, but for Ms. Bosco, 77, the issue is a matter of consistency.

“I think we have to be pro-life, but we have to be pro-life all the way,” she said.

Ms. Bosco speaks frequently about her loss, including at last week’s forum in Queens. She said she did not want to see her son’s killer executed. “We would not want his blood on our hands,” she said.