Quentin Skinner argued that several critical modern innovations in contract theory are found in the writings of French Calvinists and Huguenots, whose work was used by writers in the Netherlands who resisted submission to Spain and, later, to Catholics in England.  Francisco Suarez (1548-1617), of the Salamanca school, could be considered a former social contract theorist, who theorized natural law by trying to limit the divine right of absolute monarchy. All these groups have been led to articulate conceptions of popular sovereignty through a confederation or social treaty, and all these arguments began with proto-“State of Nature” arguments that the basis of the policy is that everyone is inherently free from submission to any government. Modern Anglo-American law, like European civil law, is based on a theory of the will of the treaty, according to which all contractual conditions are binding on the parties because they have chosen these conditions for themselves. This was not true when Hobbes wrote Leviathan; At the time, more emphasis was placed on the review, i.e. a reciprocal exchange of the benefits necessary for the formation of a valid contract, and most contracts had implicit clauses that stemmed from the nature of the contractual relationship and not from the decisions made by the parties. Accordingly, it has been argued that the theory of the social contract is more compatible with the contractual law of Hobbes and Locke`s time than with the contractual law of our time, and that certain characteristics of the social contract that seem to us to be unsanquentanomal, such as the belief that we are bound by a treaty formulated by our distant ancestors, Hobbes` contemporaries would not have seemed as foreign as we are.  The state system resulting from the social contract was also anarchic (without direction). Just as individuals were sovereign in the state of nature and thus let themselves be guided by their own interests and by the absence of rights, States now act in their own interest in competition. Thus, like the state of nature, states had inevitably come into conflict because there was no sovereign who went beyond the (more powerful) state, capable of imposing on everyone a system such as the laws on social contracts by force.
In fact, Hobbes`s work served as the basis for the theories of realism advanced by E. H. Carr and Hans Morgenthau. Hobbes wrote in Leviathan that people (“we”) need the “terrour of a certain power,” otherwise people will not respect the law of reciprocity, “(on the whole) do to others as we would.”  An empirical approach follows Schelling`s (1960) work on the theory of negotiations and games, looking at how real people negotiate and reach an agreement. Pioneers of experimental economics used laboratory experiments to study how subjects behaved in cases of divisional problems (Hoffman et al. 2000, Smith, 2003). Some of the most interesting results came, perhaps surprisingly, from asymmetrical trading games like the ultimatum game (Smith 1982).