Plenty of ideas have shifted public opinion because people argued for them in good faith. But performative extremism doesn't automatically insert ideas into the Overton window.
The best reading of the literature is that radicals can make moderates look reasonable but reduce overall support for their cause. See these recent papers for the research:
The best reading of the literature is that radicals can make moderates look reasonable but reduce overall support for their cause. See these recent papers for the research:
- "Radical flanks of social movements can increase support for moderate factions": Simpson, Willer & Feinberg 2022, https://academic.oup.com/pnasnexus/article/1/3/pgac110/66336...
- "Extreme Protest Tactics Reduce Popular Support for Social Movements": Feinberg, Willer & Kovacheff 2017, https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2911177 (this is the working paper, since the published piece is paywalled)