DOVER — After refusing for years to take a public stance on the issue, Democratic Gov. Jack Markell on Thursday said he supports an effort to repeal Delaware’s death penalty.

Markell said that if a bill to abolish capital punishment reaches his desk, he would sign it.

“The death penalty is an instrument of imperfect justice,” he said in a telephone interview from Switzerland, where he attended a gathering of business and political leaders this week.

“I thought very carefully about arguments for and against,” said Markell, who during his political career has had personal experience with life-and-death issues involving capital punishment.

While serving as state treasurer, Markell was also a member of the Board of Pardons, where he voted on five commutation requests from convicted killers, choosing all but one time to uphold the death sentence.

As governor, however, Markell in 2012 spared the life of a killer who was just days away from execution for the shooting death of his former girlfriend. Administration officials said at the time that they were unaware of any previous case in which a Delaware governor had received or approved a pardons board recommendation for commutation of a death sentence.

While saying he understands the arguments of death penalty supporters, he said his decision was swayed by the FBI’s recent acknowledgment that examiners in its microscopic hair comparison unit gave flawed testimony in more than 250 criminal cases, including death penalty cases, before 2000.

“I thought that was quite extraordinary. I’d say that was very important,” he said.

Markell’s comments came just days before a House committee takes up legislation that abolishes Delaware’s death penalty, except for the 15 inmates currently on death row.

“Obviously, the vote’s going to be next week, and I thought I should talk about it before then,” he said.

Sen. Karen Peterson, D-Stanton, chief sponsor of the repeal legislation, welcomed Markell’s decision.

“I think it finally got to a point where the governor decided he needed to speak out,” said Peterson, who refused to criticize Markell’s previous silence on the issue.

“I would rather he take his time and really believe in the position that he was taking rather than feeling pressured into taking a position because it’s politically correct or whatever,” she said.

The repeal bill cleared the Senate last month on an 11-9 vote but could face an uphill battle in the House. Peterson said she believes Markell’s support will increase its chance of passage.

The legislation mirrors a bill that passed the Senate in 2013 by only one vote before dying in a House committee. It would remove execution as a possible punishment for first-degree murder, leaving life in prison without the possibility of parole as the only sentence.

Attorney General Matt Denn, Markell’s former lieutenant governor, has said he is not opposed to capital punishment in appropriate cases, but that state law should be changed to require a unanimous jury recommendation before a judge can impose a death sentence.