Florida executed 21 prisoners when Jeb Bush served as state governor. Bush, a strong proponent of the practice, aired television ads during his failed 1994 bid for governor that attacked his opponent for going soft on the death penalty.

But in a new interview, Bush says that he's "conflicted" about the practice because his Catholic faith clashes with the families of victims seeking closure for crimes and with concerns about the length and cost of convictions and appeals.

"It's hard for me, as a human being, to sign the death warrant, to be honest with you," Bush told NBC's "Meet the Press" in an interview that aired Sunday.

"I'm informed by my faith in many things, and this is one of them," he added. "So I have to admit that I'm conflicted about this. But here's the deal — this happens in rare cases where the death penalty's given out and you meet family members that have lost a loved one and it's still in their heart. It's etched in their soul. And this is the way that they get closure? I get more comfortable with it, to be honest with you."

Aides confirmed that this is the first time that Bush has expressed concerns about the death penalty as a presidential candidate. He has no current plans to introduce potential changes to the death penalty system — a move that would inject him into a growing, emotional national debate about criminal justice reforms.

On Capitol Hill, Democrats and Republicans are pushing for changes in the length of mandatory sentences for repeat drug offenders and the repeal of the federal “three strikes” mandatory life provision, among other changes. So far, the legislative proposals say nothing about the death penalty.

Despite adopting a "tough on crime" approach as governor that included strong support for the death penalty, Bush established a commission to explore the constitutionality and morality of the death penalty in his closing days as governor in 2006. The decision was prompted by the botched execution of convicted murderer Angel Diaz, who took 34 minutes to die after two doses of the lethal drugs used to kill inmates. The commission later proposed better training for executioners and changes in the chemicals used to kill convicted criminals. But legislation introduced to enact the proposals was later shelved.

On Friday, Florida executed Jerry Correll, a man convicted of fatally stabbing his ex-wife, young daughter and two in-laws. He was the 22nd inmate to be executed under Republican Gov. Rick Scott — surpassing the 21 inmates executed during Bush's two terms as governor from 1999 to 2007.

In the interview, Bush told NBC's Chuck Todd that he now doubts that the punishment is a deterrent for crime.

"But we should reform it. If it's to be used as a deterrent, it has to be reformed," he said. "It can't take 25 years. That does no one any good. Neither the victims nor the state is solving this problem with that kind of tangled judicial process."

Concerns about the length of time the death penalty process takes dates to Bush's failed bid for Florida governor in 1994. In the closing weeks of the race against incumbent Democratic Gov. Lawton Chiles, Bush aired an ad accusing the governor of supporting criminals' rights and delaying the execution of a convicted murderer. Widely panned by Democrats and newspaper editorial boards as an inaccurate attack in poor taste, Bush later conceded that there was nothing Chiles could do to expedite the murderer's death sentence.

"I believe life is truly a gift from God, and innocent life particularly should be protected at all cost, for sure," Bush said in the interview. "But people that commit these crimes, justice can't be denied. And it shouldn't be delayed. And maybe there's a better way to do this where victims feel as though they're being served, because that should be front and center, the first obligation of the state."

The Supreme Court upheld the death penalty in June, despite the concerns of physicians worried about the cocktail of lethal drugs used to kill convicted inmates. Only nine countries in the world actively execute people, including Iran, Sudan and North Korea, according to an Amnesty International report.

Bush's comments come as he prepares to spend this week highlighting his work as Florida's governor. On Monday, he will campaign in Tampa, Orlando and Jacksonville to tout the release of a new e-book, "Reply All," that includes excerpts from the millions of e-mails he received during his eight years in office.

On Tuesday, Bush plans to campaign in South Carolina, before spending the rest of the week on a bus tour in New Hampshire, a must-win state for his faltering campaign.