text: did the federal government change during the civil war? did the federal government change during the civil war? yes, more centeralized to better prosecute the civil war. abe introduced the income tax (although it went away later until the begining of the 20th century).  before the civil war people were more likely to think of "these united states of america" as a bunch of states, it was only after the civil war that it became "the united states of america."