Updated

Legislators were expected to grant final approval to a bill that repeals the death penalty, moving Connecticut one step closer to becoming the 17th state to ban capital punishment.

Democratic Gov. Dannel P. Malloy has said he will sign the bill into law.

After years of failed attempts to repeal the death penalty, which has been on the books in Connecticut for more than 150 years, lawmakers were able to garner support by making the legislation prospective — affecting future crimes and not the 11 men currently on death row.

But the bill's critics, including Dr. William Petit Jr., the sole survivor of a 2007 home invasion that left his wife and two daughters dead, question whether the provision is constitutional and predict it will be the basis for new appeals by the 11 condemned men.

"How can you say in your heart and with your vote it should no longer be the policy of the state of Connecticut to commit anyone to death and yet at the same time say, 'Except for these 11 guys,'" asked House Minority Leader Lawrence Cafero Jr., R-Norwalk, during Wednesday's House debate. "How can you say that? How can you justify that?"

Preserving the death sentence of those still on death row is fairly unusual, although a similar law took effect in New Mexico. The governor there declined to commute the sentences of the state's two death row inmates after the repeal was signed in 2009.

Connecticut has a history of making changes to the death penalty prospective, said Rep. Gerald Fox, D-Stamford, co-chairman of the legislature's Judiciary Committee. He said in 1846, the state created distinctions between first- and second-degree murders. Prior to that change, all murders were punishable by death.

In 1951, a law was passed allowing a jury to determine whether to impose death or life in prison for a first-degree murder. That law, Fox said, was ultimately upheld by the State Supreme Court.

"There is a history behind this. It has happened before in terms of the prospective nature of our death penalty," Fox said. "I recognize the question. I understand these cases are heavily litigated and every avenue is always explored to its fullest, but that is where our law stands now."

Both advocates and opponents of the repeal bill predicted the repeal would ultimately become law. Last week, the state Senate passed the legislation on a 20-16 vote.

The bill abolishes the death penalty and replaces it with life imprisonment without the possibility of release. The Senate amended the bill to require that individuals convicted under the new law would be subject to prison conditions similar to those now experienced by condemned inmates.

Hours before the House debate, repeal proponents urged their legislators to follow the lead of the Senate. Dawn Mancarella of Milford, whose mother Joyce Masury was murdered in 1996, said she represents more than 180 individuals who have lost loved ones to murder and are backing repeal. She said they don't believe the death penalty helps them.

"Some of us have seen the loss of their loved ones all but ignored while capital cases get months, or even years, of attention," she said during a morning news conference. "Some of us have endured capital cases and are horrified that the death penalty ensnares them in a never-ending wait for execution."

Prior to last week's Senate vote, several family members of murder victims, including Petit, tried to persuade lawmakers to keep the death penalty in place. Petit, who was instrumental in persuading senators last year to oppose repeal efforts, said legislators are being "led astray" by assertions that repeal would affect those on death row, including the two men convicted of killing his family members.

Connecticut has carried out only one execution in 51 years, when serial killer Michael Ross was administered a lethal injection in 2005 after he gave up his appeal rights.

In the past five years, four states have abolished the death penalty — New Mexico, Illinois, New Jersey and New York. Repeal proposals are also pending in several other states including Kansas and Kentucky, while advocates in California have gathered enough signatures for an initiative that could go before the voters in November.