The influence of partisan news is presumed to be powerful, but evidence for its effects on political elites is limited, often based more on anecdotes than science. Using a rigorous quasi-experimental research design, observational data, and open science practices, this book carefully demonstrates how the re-emergence and rise of partisan cable news in the US affected the behavior of political elites during the rise and proliferation of Fox News across media markets between 1996 and 2010. Despite widespread concerns over the ills of partisan news, evidence provides a nuanced, albeit cautionary tale. On one hand, findings suggest that the rise of Fox indeed changed elite political behavior in recent decades. At the same time, the limited conditions under which Fox News' influence occurred suggests that concerns about the network's power may be overstated.