Final answer:
Interpretation A by Weinberg views the Mexican War and Manifest Destiny as American expansionism influenced by 'white man's burden' and self-interest, while Interpretation B by Nevins emphasizes the internal political and sectional conflicts within the Democratic Party over expansion and slavery.
Step-by-step explanation:
The student is asking to explain the differences between two historical interpretations concerning the Mexican War and Manifest Destiny.
Interpretation A, by Albert K. Weinberg, suggests American expansionism during the Mexican War was partly motivated by a sense of 'white man's burden' and contemplated the 'regeneration' of Mexicans through civilizing enterprises. It hints at a blend of national self-interest and a perceived obligation towards other peoples, wrapping territorial ambitions under the guise of benevolent expansionism.
Interpretation B, by Allen Nevins, focuses on the internal struggles within the Democratic Party over the issue of expansion and slavery. It highlights that the war exacerbated the existing fractures between Northern Democrats, who opposed the expansion of slavery, and Southern Democrats, who believed in its spread. This interpretation brings to light the political and sectional strife within the United States that was intensified by the war, rather than the external civilizing philosophies.