The decades that followed independence from Spain in 1821 transformed Mexico from a strong, stable colony to a republic suffering from economic decline, political turmoil, regional divisions and class hatred. This chaotic state hindered efforts of the young republic to meet the aggressive expansionism of the United States between 1845 and 1848.

Pedro Santoni sheds new light on Mexican political history during the conflict - a much neglected subject - through a comprehensive examination of the only Mexican political bloc that wanted war with the United States. Led by Valentin Gomez Farias, this faction was the radical federalists, who in 1846 took the name of puros.

Santoni demonstrates the reasons for the failure of the puros' efforts to gain political power and coordinate the war effort. Examining the puros' attempts to reestablish federalism in Mexico, shape public opinion, develop a civic militia and forge alliances with senior army officers and opposing political groups, Santoni maintains that the economic, social and political troubles of Mexico nullified the puros' endeavors to direct armed resistance against the Americans.

He also dispels some of the erroneous notions - that the puros and Gomez Farias were self-serving and corrupt and sold out Mexico to the United States, for example - that have been propagated by historians in the past.