Engstrom evaluates redistricting plans and their electoral results from all states from 1789 through the 1960s, revealing that districting practices systematically affected the competitiveness of congressional elections
shaped the partisan composition of congressional delegations
and, on occasion, determined control of the House of Representatives. Erik J. Engstrom offers a historical perspective on the effects of gerrymandering on elections and party control of the U.S. national legislature. Aside from the requirements that districts be continuous and, after 1842, that each select only one representative, there were few restrictions on congressional districting. Unrestrained, state legislators drew and redrew districts to suit their own partisan agendas. With the rise of the "one-person, one-vote" doctrine and the implementation of the Voting Rights Act of 1965, however, redistricting became subject to court oversight.