"[288] Amy Greenberg, in her history of the Mexican War, found Polk's legacy to be more than territorial, "during a single brilliant term, he accomplished a feat that earlier presidents would have considered impossible. With the help of his wife, Sarah, he masterminded, provoked and successfully prosecuted a war that turned the United States into a world power."[289] Borneman noted that in securing this expansion, Polk did not consider the likely effect on Mexicans and Native Americans, "That ignorance may well be debated on moral grounds, but it cannot take away Polk's stunning political achievement."[290] James A. Rawley wrote in his American National Biography piece on Polk, "he added extensive territory to the United States, including Upper California and its valuable ports, and bequeathed a legacy of a nation poised on the Pacific rim prepared to emerge as a superpower in future generations".