A majority of Americans favor life imprisonment without parole over the death penalty for convicted murderers, a first in ABC News/Washington Post polls.

Given a choice between the two options, 52 percent pick life in prison as the preferred punishment, while 42 percent favor the death penalty - the fewest in polls dating back 15 years. The result follows a botched execution by lethal injection in Oklahoma in late April.

See PDF with full results, charts and tables here.

Without an alternative offered, 61 percent continue to support the death penalty, matching 2007 as the fewest in polls back to the early 1980s. That's down sharply from 80 percent in 1994.

Clearly there's remaining ambivalence; when offered the option of life imprisonment with no chance of parole, 29 percent of death penalty supporters prefer the alternative.

INJECTIONS - Another result finds that most supporters of capital punishment hold that position even if lethal injections became unavailable or were outlawed. Just 16 percent of death penalty supporters say either of those would constitute grounds for doing away with capital punishment; eight in 10 would shift to another method, e.g., the electric chair or gas chamber.

Lethal injections have come under scrutiny, on issues including the unavailability of customarily used drugs, following the 43-minute botched execution of inmate Clayton D. Lockett in Oklahoma. A new law in Tennessee allows for electrocution if lethal drugs are not available.

Support for the death penalty is higher in the 32 states that have it, 64 percent, vs. 54 percent elsewhere. In a wider gap, people in death-penalty states divide about evenly in their preference for capital punishment vs. life without parole, while in other states life imprisonment is preferred by a 20-point margin.

This survey, produced for ABC by Langer Research Associates, measures views on the death penalty in general. Previous polling has shown that attitudes on capital punishment can vary widely depending on the nature and circumstances of the crime.

GROUPS - Views on capital punishment range among groups. Fifty-six percent of women support the death penalty, rising to 66 percent of men. And women prefer life in prison to the death penalty by 57-37 percent, while men are evenly divided.

There's also a vast gap by race; whites are more likely than nonwhites to support the death penalty, and to prefer it over life in prison, by 23- and 22-point margins. The gaps are widest comparing whites to blacks, a group that's generally skeptical of the criminal justice system. Their support for the death penalty is lower than that of any other group.

Among other groups, support for the death penalty peaks among evangelical white Protestants and Republicans, at eight in 10 each, dropping to 47 percent among Democrats. It's 20 points higher among conservatives than liberals.

Preference for capital punishment over life in prison follows similar patterns, peaking at 65 percent among evangelical white Protestants (vs. 36 percent of their non-evangelical counterparts). It's 30 points higher among Republicans than Democrats, and 25 points higher among conservatives than liberals.

In terms of change, preference for the death penalty vs. life in prison is down by 8 points since 2006, with the most pronounced drops (by 10 to 20 points) among non-evangelical white Protestants, seniors, nonwhites, less-educated adults, liberals and independents.

METHODOLOGY - This ABC News/Washington Post poll was conducted by telephone May 29-June 1, 2014, in English and Spanish, among a random national sample of 1,002 adults, including landline and cell-phone-only respondents. Results have a margin of sampling error of 3.5 points, including design effect.

The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by Abt-SRBI of New York, N.Y.