A data-driven investigation into Pennsylvania's role as one of the nation's most prized presidential battlefields.

The Commonwealth of Pennsylvania is no stranger to being at the center of American politics. It was the site of the signing of the Declaration of Independence and the establishment of the United States Constitution, and it even served as the nation's capital during the 18th century. It has also been one of the most highly coveted states in presidential elections. With its large share of electoral votes and a generally competitive partisan balance, the Keystone State has traditionally drawn heavy campaign activity and often played a key role in determining who held the presidency. How did Pennsylvania become the nation's consummate ”swing state” at the quarter point of the 21st century? Drawing on nearly 30 years of public opinion polling data, this book provides a framework for understanding the main factors that have placed the Keystone State at the center of American politics.

Berwood A. Yost is the Director of the Center for Opinion Research and the Director of the Floyd Institute for Public Policy at Franklin & Mashall College, USA.

Christopher Borick is adjunct professor of political science at Lehigh University, USA.