Since 1996, death sentences in America have declined more than 60 percent, reversing a generation-long trend toward greater acceptance of capital punishment. In theory, most Americans continue to support the death penalty. But it is no longer seen as a theoretical matter. Prosecutors, judges, and juries across the country have moved in large numbers to give much greater credence to the possibility of mistakes -- mistakes that in this arena are potentially fatal. The discovery of innocence, documented here through painstaking analyses of media coverage and with newly developed methods, has led...