At 2:18pm ET on October 3rd, 2018 nearly all Americans phones buzzed and vibrated as they received a notification reading Presidential Alert: THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed. While the alert system was the product of a bipartisan endeavor under the Bush and Obama administrations to improve the government’s capacity to warn Americans in the case of a natural disaster, and received scarce media attention when it was established, media coverage preceding its inaugural test depicted an intensely partisan reaction. Alarmist headlines warned of an inevitable barrage of text messages from Trump, calls to protest the alert lit up Twitter with hashtags encouraging Americans to shut off their phones or cancel their wireless plans, and critics even filed lawsuits to stop the alert altogether. As The Atlantic synopsized in a headline on the day of the alert, ``What should have been a routine, required national test of the Wireless Emergency Alerts system has become a crucible for public distrust.” While a large literature explores how partisanship divides the public on hot-button political issues, we know far less about the extent to which partisanship and partisan bias interfere with less salient bipartisan issues. To what extent does growing partisanship influence support for policies that are bipartisan in nature? We conducted a national survey experiment during the alert itself, rapidly collecting a large sample of U.S. adults in a narrow time interval preceding the alert by simultaneously recruiting online survey respondents from multiple panels. We then exploited the predetermined timing of the alert to randomize whether respondents answered questions related to the alert immediately before or after receiving it, enabling us to measure the extent to which receiving the alert affected attitudes differently across party lines.