As the assaults on Leipzig's institutions unfolded, Straube stepped up his reading regimen. He now had more free time and wished to keep his mind nimble, sharpening the intellectual faculties he was sure the cantorate's unrelenting musical demands had blunted. Perhaps his insatiable consumption of literature during this period—classical and contemporary, fiction and non-fiction, musical and socio-political history alongside analysis of current events—betrayed an escapism from the deterioration of the cultured world he thought he knew. But as best he could, he also was trying to make sense of that world as it splintered, in part by situating the present in a long narrative arc.

In November 1940 he had plunged into Heinrich Mitteis's Der Staat des hohen Mittelalters, a demanding study in comparative constitutional history of the Middle Ages. Like Haller's Papsttum, this one bore Straube's name as the dedicatee, here in gratitude for “the deepest impressions of my youth.” The eminent legal historian and medievalist Mitteis had studied at the Thomasschule and the University of Leipzig during Straube's virtuoso years and, again like Haller, had bonded with him over common interests in music and history. Mitteis had shown such promise as a musician that Straube had drawn on him to conduct the Bach-Verein. On the cantor's urging he ultimately would pursue an academic career. In the introductory chapter of his book Mitteis wrote that “already the [medieval] Germanic state rested completely on relationships between leaders and those led,” equating this incipient notion of government to “the strong feeling of attachment of all members of the Volk to success and failure,” in which they were invested equally. “Hence also the right of the people to rebel against the king if he should fail to show true loyalty.” Further, “the Germanic world is a world of rights,” and “the deepest sense of legal history” lay in the tracing of how the notion of rights is demonstrated through time. Mitteis's treatment of classed society's relationship to just systems of governance touched a topic that long had piqued Straube's interest. It was at the heart of his concern for “the masses” and their posture toward “the national cause,” the issue he had articulated to Haller back in 1922.