Well outside of the range of prevailing assumptions about the racially motivated murders in Charleston, S.C., the explanations for this catastrophic episode lie in the historical event known as the Compromise of 1877, and in the failure of professional psychologists to provide a compelling synthetic account of why people do what they do.

Perpend: In the aftermath of the Civil War (1861 to 1865), there was an effort known as Reconstruction (1866 to 1877) to bring former slaves specifically and African-Americans generally into the civic fabric of the nation. But in 1876, Rutherford B. Hayes (Republican) and Samuel Tilden (Democrat) ran in a virtual dead heat in pursuit of the presidency. More than a century before hanging chads entered the national lexicon in the aftermath of presidential election 2000, the vote turned on Florida: The election was in dispute in that state, the electoral votes of which would swing the result to one side or the other.

A deal was cut that determined the course of United States history thereafter. Democrats told Republicans that they would concede the Florida vote and thus the election if Hayes and cronies would agree to remove federal troops from the South. Out the troops came, so that the Reconstruction amendments (13th: abolished slavery; 14th: provided full citizenship rights to all adult males; 15th: guaranteed the vote to all adult males) to the U.S. Constitution could not be enforced, as long as the federal executive winked at the ensuing violence, and the federal judiciary continued to rule that the "law of the land" could not be enforced nationally because of states' rights.

The years from 1877 until 1964 were just as difficult and violent for African-Americans as were the centuries of slavery. The "separate but equal" principle advanced in the Supreme Court decision of Plessy vs. Ferguson (1896) facilitated Jim Crow, the Black Codes and the American precursor to apartheid. Sharecropping proved another form of economic bondage. Vigilantes lynched more than 4,500 people (a third of them white folks in the Wild West; most of the others black folks in the Mean South) between 1882 and 1965. Migrants heading north from the Southern states during the first two-thirds of the 20th century found greater economic opportunity, but they also experienced familial dislocation and racially discriminatory residential housing covenants that shuttled them to certain areas within urban communities. Ironically, civil-rights legislation and fair-housing laws of the 1960s facilitated not only white flight but also the movement of the African-American middle class to the suburbs, a phenomenon witnessed both in the North and in the South.

Left behind at the urban core were many people suffering extreme poverty and familial dysfunction. Central school districts were overwhelmed and have not, for at least 35 years (since crack cocaine hit the streets and gang violence worsened), provided anything remotely resembling an acceptable K-12 education. African-American students typically failed to graduate from high school, and no one got a knowledge-intensive K-12 education in history or any other subject because the education establishment devalues knowledge in favor of shibboleths such as "critical thinking" and "lifelong learning," protective shields against failure to teach historical knowledge sets that most teachers themselves do not understand.

So a Dylann Roof appears somewhere on our national landscape with disturbing regularity. Roof blew away the lives of nine fellow humans that he was too ignorant to recognize as fellows. But he was already emotionally dead: a failure in high school, reared in familial fragmentation, living in his car, drug-dazed at malls, possessing a skewed historical opinion in the absence of historical knowledge — the latter a condition abiding in an illness abhorrently manifested in a 21-year-old white male but shared with the American people in general. Very few Americans comprehend how the deal cut in the Compromise of 1877 validated racism that existed most explicitly into the 1960s but abides today in Ferguson, Mo.; Baltimore; Charleston; or north Minneapolis. The particularly ignorant and violent Dylann Roof is the natural extension of our own ignorant and violent selves. We all murdered those nine sincerely religious African-American people by creating the climate of historical ignorance and racial insensitivity that is nationally ubiquitous.

Meanwhile, professional psychologists study the brain, cognitive processes and social psychological phenomena, but they fail to take a stand in a consensus account fundamentally explaining why people do what they do. The psychology profession is deeply culpable in abetting simplistic explanations of "evil" as the reason why a Dylann Roof blows nine fellow humans out of this earthly sojourn; psychologists offer no compelling explanation of their own.

A behaviorist such as I is clearer: There is no such thing as free will. People do what they do because of reinforced behaviors from their own experiences, or because of some biological condition present at birth or acquired typically in the early years of life. Since, therefore, behavior is either biologically determined or environmentally reinforced, there can be no justification for capital punishment except in some crude effort to make the Dylann Roofs of our nation an extreme example of a condition that abides in the nation as a whole, thereby dissuading us all from our worst behavioral potential.

Rather than wring our hands seeking explanations for why the good folks studying the Bible in Emanuel African Methodist Episcopal Church were brutally murdered by this most violent extension of our own propensities, we should study and comprehend history, embrace knowledge rather than excuse ourselves for not having it, and face the psychological reality of human behavior even if the professionals cannot or will not.

Gary Marvin Davison is the author of eight books, including three on African-American history and society; he is the director of the New Salem Educational Initiative in north Minneapolis and blogs at www.newsalem education.blogspot.com.