In the heyday of the electric chair 60 years ago, execution was not so certain as it is today.
Then, as many as 20 percent of condemned prisoners had their sentences commuted to life in prison.
"Traditionally, clemency has been associated with mercy or grace," said Austin Sarat, a law professor at Amherst College.
Even Charles Manson, one of the most notorious murderers in America, was granted clemency in 1972 when the California death penalty was declared unconstitutional.
Now, with two-thirds of the country supporting capital punishment, clemency is rare and, as much as anything, a political liability.
"Clemency can be seen, when it's exercised by a governor, as a sign of weakness or not being tough on one of the country's great social issues," said Kermit Hall, a legal scholar who is president of the University at Albany, State University of New York.
California Gov. Arnold Schwarzenegger has said he's keeping an open mind about Stanley "Tookie" Williams, convicted in 1981 of murdering four people.
"That's what you do," Schwarzenegger said. "But they are very heavy responsibilities."
Every governor is shadowed by the political ghost of Willie Horton, the murderer whose furlough was famously used in the 1988 presidential campaign to paint then-Gov. Michael Dukakis, D-Mass., as soft on crime.
Since 1976, only 230 death sentences have been commuted to life -- 167 of those in a single day when former Illinois Gov. George Ryan declared the death penalty "arbitrary and capricious."
Not one sentence has been commuted because the condemned is reformed or redeemed by good works, as claimed by Williams, who wrote nine books discouraging children from a life in gangs.
"If governors granted clemency petitions on the basis of redemption, you'd have many death row inmates who suddenly find themselves redeemed," Sarat said.
In 1998, then-Gov. George Bush of Texas said he could not judge the sincerity of Karla Faye Tucker, who said she found God on death row. Bush said he would leave judgement to that same god, and allowed her execution.
If his sentence is not commuted, Williams is scheduled to die by lethal injection early Tuesday.
ABC News' Brian Rooney originally reported this story for "World News Tonight" on Dec. 11, 2005.