Before revision:  I then analyze identification of causal direct and spillover effects under one-sided noncompliance, and propose simple estimators that are consistent and asymptotically normal under mild conditions. I use the proposed methods to analyze an experiment on social interactions and voting behavior.
After revision:  I then analyze identification of causal direct and spillover effects under one-sided noncompliance, and show that these effects can be estimated by 2SLS. I illustrate the proposed methods to analyze an experiment on social interactions and voting behavior.