The authors point out that today it is necessary to reconsider the political, philosophical and legal opinion of the leading theorist of Ukrainian constitutionalism of the second half of the 19th century. Mykhailo Drahomanov and the current strengthening of the progressivism movement in the USA, Latin America and Europe, which, probably, can lead to similar trends in Ukraine and to the revival of the current of progressivism in Ukrainian constitutionalism in new circumstances. That is why the article is devoted to the study of the constitutionalist concept of Mykhailo Drahomanov. The paper analyzes the political and philosophical sources and characteristic features of the political and legal thought of an outstanding Ukrainian public and political figure of the second half of the 19th century. A conclusion is made about the evolutionary-socialist (progressive) nature of his constitutional thought.
 The authors come to the conclusion that M. Drahomanov was indeed faithful to the liberal-democratic values of freedom of speech, thought, secularization, democracy, local self-government, but at the same time he did not share the value of freedom of entrepreneurship and private property, he did not understand the fundamental relationship between political freedom, according to which he supported, and the market economy, which he considered more of a disaster than a guarantee of constitutionalism. The dominance of the ideology of political freedom in the "Foundations Project" does not reflect the essence of the author's constitutionalism, it is a significant and integral part of it, which serves as a prologue to the implementation of other foundations of building the society dreamed by M. Drahomanov. His ideal of social organization was based on cosmopolitanism and democratic evolutionary socialism, which determines the specificity of this model of constitutionalism, its exclusivity, since in the future constitutionalist thought in Ukraine became more and more polarized - to the left, towards Marxism and populism, to the right - towards conservatism and nationalism. Therefore, M. Drahomanov became the founder of the left tradition in Ukrainian constitutionalism and the only representative of the progressivist trend in this tradition, that is, the trend that represented the evolutionary-democratic wing in the socialist movement and philosophy, which today is gaining strength in the person of such politicians as Bernie Sanders, Alexandria Ocasio- Cortes in the USA or Jean-Luc Mélenchon in France. Given the popularity of progressivism in the world and in Ukraine, Drahomanov's ideas can flourish, reborn in circumstances more favorable to this ideology.