In federal democracies, political parties often invest in local politics for national gains. This strategy is crucial, particularly in noisy democracies where politicians need to find informational shortcuts to attract inattentive voters. I define this strategy as political boosting, and investigate its dynamics in Brazil, a textbook example of a fragmented party system. Using a regression discontinuity design (RD), I show that parties in Brazil boost their national performance earning more votes on House elections in districts where their members control the local office. Additionally, by using a novel Bayesian LASSO algorithm to address data sparsity in RD designs, I find the existence of a pro-large party bias on boosting. Ultimately, my analysis highlights how the institutional strength and differential access to pork explain why boosting is more effective for large parties. By disentangling the effects of winning local elections, the paper explains a venue by which parties build electoral strength in fragmented democracies.