With the Natural Law side making such concessions, it is difficult to believe that both sides could not have come to a common understanding. The egoists believed they were reducing the concept of rights to its proper place as an artificial, but useful construct with which to organize society. Tucker continued to believe in what he called 'society by contract', but he came to view rights as the by-products of contracts between individuals, not as entities existing on their own. John Kelly leaped to attack Tucker's theory as being self contradictory. Kelly was pointing out what he believed to be the major philosophical flaw of egoism.
Contracts make sense only in the context of rights.
To claim that rights spring from contract is to invert the logical order. A full and dispassionate debate on this point would have been a fascinating chapter in American individualism. It never occurred. Each side became so bitter and ad hominem that productive discussion became impossible. And, so, the fledging individualist movement splintered and shrank.