Past work suggests that partisan attachments isolate citizens from encountering elite messages contrary to their points of view. Here, we present evidence that partisan attachments not only serve to filter the information citizens receive from political elites; they also work in the other direction, isolating politicians from encountering potentially contrary perspectives from citizens. In particular, we hypothesized that Americans prefer expressing their opinions to politicians who share their party identification and avoid contacting outpartisan politicians. Three studies—drawing on a mixture of observational, field experimental, and natural experimental approaches—support this hypothesis: Citizens prefer to “preach to the choir,” contacting legislators of the same partisan stripe. In light of evidence that contact from citizens powerfully affects politicians’ stances and priorities, these findings suggest a feedback loop that might aggravate political polarization and help explain how politicians of different parties could develop different perceptions of the same constituencies.