This study builds on existing literature demonstrating the conditional effects of contextual and conversion factors on the relationship between money and votes in state legislative elections. A conditional theory of the impact of spending in state legislative campaigns is developed, emphasizing that the effectiveness of expenditures should vary according to the number of "up for grabs" voters in a district, candidate quality, and strategic decisions about when to enter a race. Using an original data set of elections to state legislatures in nine states, the analysis provides evidence that the political and institutional context of a race has a significant impact on the effectiveness of campaign spending. Specifically, the percentage of registered independents in a district, the presence or absence of term limits on legislators, and the level of professionalism of a legislature each significantly condition the impact of money.