The article provides an analysis of the systemic transformations in Poland in the summer and autumn of 1989 r. The main impulse behind these transformations were the Round-table agreements between the representatives of the former Communist regime and independent social movement organizations comprised mostly of the members of the 'Solidarity' trade union.. They have resulted in an amendment of the Constitution of 7 April 1989 as well as the adoption of many other statutes. The arrangements of the Round-table discussions and the amendments of the Constitution were both a product of political compromise. These changes included, in particular, the establishment of the office of President of the Republic and the second chamber of parliament. The article contains a detailed analysis of powers of the two new bodies, as well as new powers of already existing bodies. However, the above-mentioned compromise was rejected by the People in the parliamentary election of 4 and 18 June 1989. In the opinion of the author, the result of that election, meant in fact the restoration of the principle of sovereignty of the Nation (although absent from the text of the Constitution), and the said principle had to lead, in practice, to an interpretation incompatible with the intentions behind the above-mentioned political compromise.