The question of whether or not campaigns have an impact on vote choice and mobilization has been debated by a number of scholars. In this dissertation, I explore this question using data from presidential nomination elections, as I argue this setting allows us to better understand campaign effects than the general election. Due to the intra-party nature of nomination contests, voters are not able to rely on partisanship in making their decision among candidates. Instead voters need to use some other source of information in making their decisions about 1) whether or not to vote and 2) which candidate to vote for. I explore these two decisions in depth in my dissertation, focusing mainly on the effect visits have on both. I have compiled data on both the timing and location of all of the candidate visits throughout the presidential nominating contests of 2008, across both the invisible primary and election year campaigns. Using this unique dataset, I explore the different ways in which state visits affect presidential nomination outcomes. Specifically, I investigate the strategy behind the visits, whether or not visits increase turnout, and how visits affect vote choice. By examining these different aspects of nominating campaigns, I am able to address a number of different literatures and theories, including those focused on candidate strategy, presidential nominations, political communication, and whether or not campaigns matter.