Thomas Hobbes is considered the father of political science, though there are plenty who disagree with his philosophical arguments, both now and in his day.
The ultimate realist, Hobbes argued that because of man's fear of death, and to escape a life that is "nasty, brutish and short", mankind enters into a social contract, in essence, for his own survival. But Hobbes resembles Machiavelli in terms of the government that emerges from such a contract.
So one criticism is that there is nothing democratic or just about the government the contract produces, rather it is anti-democratic out of necessity. In the modern day, our understanding and value of the contract is that it is an agreement by both parties. In Hobbes philosophical world, the contract could only be made in the original bargain, as once it is, free will is submitted to the dictatorship he envisioned, and subsequent generations would have no say in its continuance short of staging a revolution.
Contrast Hobbes' beliefs with those of Rousseau or John Locke, who have very different conceptions of the social contract.