"[187]
Historian Larry Gara, who authored a book on Pierce's presidency, wrote in the former president's entry in American National Biography Online:[188]

He was president at a time that called for almost superhuman skills, yet he lacked such skills and never grew into the job to which he had been elected. His view of the Constitution and the Union was from the Jacksonian past. He never fully understood the nature or depth of Free Soil sentiment in the North. He was able to negotiate a reciprocal trade treaty with Canada, to begin the opening of Japan to western trade, to add land to the Southwest, and to sign legislation for the creation of an overseas empire [the Guano Islands Act]. His Cuba and Kansas policies led only to deeper sectional strife. His support for the Kansas–Nebraska Act and his determination to enforce the Fugitive Slave Act helped polarize the sections. Pierce was hard-working and his administration largely untainted by graft, yet the legacy from those four turbulent years contributed to the tragedy of secession and civil war.
