Do American politicians that clearly violate democratic norms lose significant public support, or does public opinion impose little constraint on anti-democratic politicians? Existing studies have examined this fundamental question using hypothetical survey experiments which, while valuable, suffer from ecological validity and weak treatment concerns. I overcome these problems by studying a novel quasi-experiment created by the fact that Donald Trump's incitement of the January 6 insurrection unexpectedly occurred while Gallup was conducting a nationally representative public opinion survey using random digit dialing. Comparing party identification among respondents that happened to be interviewed just before, and just after, January 6, 2021 suggests that the Republican Party retained 78% of its pre-insurrection support base during the first 1.5 weeks. Even this modest loss was short-lived---in February 2021 the Republican Party already stood at 93% of its pre-insurrection support level. While not zero, the public constraint on anti-democratic behavior is remarkably limited.
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