The article is devoted to the formation and crisis of the “mainstream” – the system of nation-state governance based on the symbiosis of the right and left ideological approaches. Formation of this system has occurred in the developed countries during the 1990s – early 2000s. Important conditions were as follows: the collapse of the Soviet system, the acceleration of globalization and economic growth, the rise of the middle class and the dominance of economic determinism in the decision making. At present, this governance system is in crisis. The erosion of middle class threatens the stability of its democratic procedures. Traditional voters of the center-left and the center-right are no longer willing to support their parties. The challenges from alternative parties and alternative political movements are becoming stronger. The victory of Donald Trump in the presidential elections in the United States, “Brexit” in the UK, the defeat of Renzi’s center-left government in the constitutional referendum and electoral successes of the “Five Stars” movement in Italy provoke further destruction of the “mainstream” core. The growing number of alternative movements’ supporters is increasingly affecting the traditional parties. The “alternatives” are closely connected with well-known “populism”, but they go beyond it in the direction of destruction of the existing consensus. “Alternatives” appeal to the citizens directly, avoiding “filters” of party structures. They seek the removal of the “political correctness”. The alternative movements have currently found a form that allows them to seriously harm the mainstream. However, they do not have content that is able to replace mainstream management practices. Nevertheless, a simple return to a period of sustainable and competitive party-political systems that existed prior to mainstream formation is also impossible. The deepening political crisis will create new forms of alternative policies with varying degrees of their success. At the end of the article the authors make conclusion about the impact of alternative movements’ rise on the contemporary political process.