Maritain's critique is based on an empirical or historical claim. That is he looks to the actual history of regimes and especially the struggle of regimes in the twentieth century. Both Hitler and Stalin claimed to learn from Machiavelli and be practitioners of his art. Maritain refers to this as the artistic or technical view of politics. Mastery is simply an art of manipulating men and materials to achieve one's goals.
Rationality is nothing but technical rationality.
The artistic view leads to immediate success or the success of life span, but it is dubious if the doers evil can actually sustain a regime over many generations. In 1950 Maritain predicted that great totalitarian power in the Soviet Union would collapse of its own internal rot. He called it a huge Machiavellian robot which possessed vast external power but lacked the internal power of truth and virtue. Ultimately the strength of the free democratic regime will be the very free initiatives and open government that provide a ceaseless flow of energy throughout the social body and political regime. It depends upon the People's means of control over the power of the state.