Publisher Johnson and historian Spencer shared a common moral purpose with respect to their aspirations for historical literature. Their convictions and sympathies were strongly connected to nationalistic and patriotic concerns, and their personal styles and intellectual outlooks were mutually grandiose. As a writer, Spencer was every bit as heavy-handed in his prose as Johnson was in the packaging of his works, Spencer’s lofty pronouncements and allegorical intentions serving as the “verbal counterpart of gilt stamping on gift-book covers.”  In the introduction to the History of the United States, Spencer outlined his hopes for the moral revolution in America that Johnson desired. Spencer argued that the historian’s traditional commitment to truthfulness and impartiality, while sacred, must be directed at eliciting the past’s “higher purposes,” and his expressed authorial goal was “to present a truthful, impartial, and readable narrative” of the divine “progress of that mighty Republic which now extends from ocean to ocean, and which is moving onward, year after year, with gigantic strides, to increased power and importance among the family of nations.” 
Spencer and Johnson shared other convictions, hopes, and fears for the nation which they expressed throughout the volumes of the History of the United States. Unlike John Frost, Spencer made no claims to objectivity or non-partisanship on these matters. “I do not . . . make any pretence to have written what is contained in the following pages in a state of indifference with regard to the points of issue, whatever the points may be,” Spencer noted. “It would be idle to suppose that any American, of ordinary intelligence, has not some distinct views as to the main subjects, which have been under discussion among a people who have the amplest liberty to write, speak, and set forth in any way they choose, their opinions and views on any and all topics. Hence, I avow, without hesitation, that my convictions and sympathies are very clear and settled in my own mind.” 
Among the issues that Spencer advocated most strongly was an end to slavery, a topic on which he showed little restraint. Nowhere does a work like the History of the United States assert the authority of the written word more than in the ministerial dogmatism of Spencer’s prose polemic against the “detestable commerce” of the enforced servitude. Slavery reflected poorly on the character of a nation whose “moral sense” was “becoming blunted,” Spencer noted with candor on Johnson’s behalf, and whose history was marred by a grave, unspeakable sin that introduced the “elements of evil, and tendencies to discord and ruin.” 
Despite the fact that Spencer and Johnson shared a common set of core beliefs that gave the History of the United States a greater consistency than Frost’s Pictorial History, relations between the historian and the publisher were sometimes strained by financial concerns as they had been for Frost and Walker. “[H]aving done a very large amount of work for [publishing] houses in New York, I may claim some right to speak on a matter wherein publishers and authors hold quite opposite views,” Spencer later wrote. “From an author's point of view, I think that the publishing fraternity are not usually as liberal as they might be, without harm to themselves; to which their reply is, that authors and literary men are continually seeking large and even extravagant prices for their labors.” 
Discouraged as well by the lack of an international copyright law that encouraged European firms to pirate his works and American firms to underpay authors at home in favor of stealing the works of English writers, Spencer argued that publishers “manifestly have all the advantage on their side.” They “pay nothing, or almost nothing, for the brain-productions of English writers, and they grow rich; while American authors, as a rule, are never known to make fortunes by writing books, or in fact anything like fortunes.” Spencer lobbied for an international copyright to protect authors both at home and abroad from such ruthless piracies, and he railed against the “scandalous wrong done to native literature” which he characterized as “a great shame [in] every way."  All these considerations left Spencer feeling a bit taken advantage of in his dealings with Johnson, although they collaborated for twenty years on numerous illustrated projects.