In 1953 Robert Penn Warren published Brother to Dragons, a narrative poem based on the crimes [of Lilburne Lewis, Thomas Jefferson's nephew]. He organized it as a dialogue of disembodied voices conversing long after the event, in an unspecified place. Instead of making the incidents themselves the substance of his poem, Warren treated those as starting a debate on "the human condition," particularly the extent of men's innate virtue or depravity. To suit his plan, he not only altered some of the facts; he not only added some fictitious characters; but he also planted himself and Thomas Jefferson in the poem, giving these outsiders many long speeches. Warren has now carefully revised and shortened Brother to Dragons for a new publication, altering many details, reassigning speeches, breaking up long lines, and giving the verse a dryer texture.

In Warren's telling, although the sickening episodes emerge gradually from the give...