Ten of the 12 states without capital punishment have homicide rates below the national average, FBI data shows, while half the states with the death penalty have homicide rates above the national average.
In a state-by-state analysis, The Times found that during the last 20 years, the homicide rate in states with the death penalty has been 48 percent to 101 percent higher than in states without the death penalty.
The study also found that homicide rates have risen and fallen along roughly symmetrical paths in the states with and without the death penalty, suggesting to many experts that the threat of the death penalty rarely deters criminals.
"It is difficult to make the case for any deterrent effect from these numbers," said Steven Messner, a criminologist at the State University of New York at Albany, who reviewed the analysis. "Whatever the factors are that effect change in homicide rates, they don't seem to operate differently based on the presence or absence of the death penalty in a state."
That is one of the arguments most frequently made against capital punishment in states without the death penalty â€“ that and the assertion that it is difficult to mete out fairly. Opponents also maintain that it is too expensive to prosecute and that life without parole is a more efficient form of punishment.
Prosecutors and officials in states that have the death penalty recognize that it is difficult to make the case for deterrence, but they contend that there are powerful reasons to carry out executions.
Rehabilitation is ineffective, they argue, and capital punishment is often the only penalty that matches the heinousness of the crimes committed. Furthermore, they say, society has a right to retribution, and executions can bring closure for victims' families.
Polls indicate that these are the views held by most Americans. And certainly, most states have death penalty statutes. Twelve states have chosen otherwise, but their experiences have been largely overlooked in recent discussions about capital punishment.
"I think Michigan made a wise decision 150 years ago," said the state's governor, John Engler, a Republican. Michigan abolished the death penalty in 1846 and has resisted attempts to reinstate it. "We're pretty proud of the fact that we don't have the death penalty," he said, adding that he was opposed to the death penalty on moral and pragmatic grounds.
Mr. Engler said he was not swayed by polls that showed 60 percent of Michigan residents favored the death penalty. He said 100 percent would like not to pay taxes.
In addition to Michigan, and its Midwestern neighbors Iowa, Minnesota, North Dakota and Wisconsin, the states without the death penalty are Alaska, Hawaii, West Virginia, Rhode Island, Vermont, Maine and Massachusetts, where an effort to reinstate it was narrowly defeated last year.
The homicide rate in North Dakota, which does not have the death penalty, was lower than the homicide rate in South Dakota, which does, according to FBI statistics for 1998. Massachusetts, which abolished capital punishment in 1984, has a lower rate than Connecticut, which has six people on death row; the homicide rate in West Virginia is 30 percent below that of Virginia, which has one of the highest execution rates in the country.
Other factors affect homicide rates, of course, including unemployment and demographics, as well as the amount of money spent on police, prosecutors and prisons.
But the analysis by The Times found that the demographic profile of states with the death penalty is not far different from that of states without it. The poverty rate in states with the death penalty, as a whole, was 13.4 percent in 1990, compared with 11.4 percent in states without the death penalty.