Existing research suggests that overt undemocratic behavior by elected officials is insufficiently punished by American voters to electorally discourage democratic backsliding. Evidence for this proposition comes primarily from hypothetical survey experiments with relatively weak treatments. I test this hypothesis using a natural experiment with a powerful treatment: Donald Trump's incitement of the insurrection of the U.S. Capitol on January 6, 2021. The insurrection was unexpected to the general public, did not coincide with other events that could plausibly affect public opinion, and occurred while Gallup was conducting a nationally representative survey using random digit dialing. Comparing vote choice intention among respondents that were interviewed just before, and just after, the insurrection occurred suggests that the insurrection caused a 10.8% decline in support for the Republican Party, and an 8.4% increase in support for the Democratic Party. Politicians interested in winning elections have strong incentives to avoid insurrection-like events from occurring.
Shortened manuscript and changed title.