On the ground of comparative analysis the authors characterized the status, problems and development tendencies of the constitutional and legal institutions in the country that ensure functioning of the check and balances system of Ukrainian government organization model. The authors considered the ideas of governmental rationalization within the context of actual ensuring people’s sovereignty as the basis of constitutionalism, defined ways to reform and improve the interaction between such constitutional authorities as: the President, the Parliament, the Government, the Constitutional Court. There is expressed an opinion that exactly through democratic elections and parliamentary activity the government should acquire legitimacy and at the same time be accountable to and controlled by the Parliament. Instead, upon conditions of giving the President the «standby authorities» the latter is provided with sufficient means for solving parliamentary or governmental crises.
Keywords: constitutionalism, people’s sovereignty, President, parliament, vote of trust, interpellation