Abstract. The article examines the evolution of right-wing radicalism and extremism in the United States during the period from 2015 to January 2021 and their destructive impact on elections and power transit. The main drivers of radicalization are explored, with special attention paid to the role of conspiracy theories, in particular the QAnon phenomenon. The article analyzes how the Internet in general and social networks in particular created echo chambers and accelerated the spread of radical ideas. Distinctions are made between the more traditional forms of radicalism and the new generation of radicals (that flourished under the Donald Trump administration). Righ-wing radicalism of the new generation is dominated by cultural libertarianism, comprised of “alt-right” and “alt-light” movements, antagonistic towards left-wing radicalism. While the Trump administration underplayed the rise in right-wing extremism, it considerably overstated the threat of left-wing radicalism. Special attention is paid to thе role of the media, including its growing lack of neutrality and emergence of the ecosphere for conservative viewers where fakes and conspiracy mindsets thrive. Anti-democratic behavior of the president and the Republican Party are explored, including deliberate misleading of voters and denial of the presidential election results. The storming of the Capitol on January 6, 2021 is interpreted as a natural progression of the above-mentioned trends. In conclusion, the forecast of future trends is made. These trends include persistence of populist sentiments, the increasing role of the alt-right, persistence of street violence, and the growing acceptance of anti-democratic behavior. All of this presents a serious challenge not only for the Republican Party, but also for the U.S. political institutions in general.