The bigger divide on the death penalty is between whites and African Americans. While 75 percent of whites say they would back the use of the death penalty were Tsarnaev convicted, the support among African Americans barely goes past the midpoint: 52 percent of African Americans would support the death penalty, and 43 percent would oppose it.

Hispanics also are less likely than whites to support the death penalty in this instance: 62 percent would support it; 35 percent would oppose it.

The large gap between whites and blacks has probably more to do with the death penalty itself than this particular case. In a recent Washington Post Maryland poll, 63 percent of whites and only 37 percent of African Americans said they favor the death penalty for people convicted of murder.