No man has the obligation to put his life on the line unless to do so would cause the downfall of the sovereign. Hobbes states that "when the defence of the commonwealth, requireth at once the help of all that are able to bear arms, every one is obliged; because otherwise the institution of the commonwealth, which they have not the purpose, or courage to preserve, was in vain" (270). The only reason to set up a commonwealth is to exit of the State of Nature or State of War and enter the State of Man or State of Law. Since, however, there is no authority or power to enforce a covenant between commonwealths, all commonwealths are in a State of War with each other, and it is the obligation of every man in a commonwealth to defend against the enemy in time of need. If the citizens in a commonwealth refuse to defend the commonwealth, the covenant between the citizens is void and the commonwealth reverts back to the State of Nature in which every man is at war with every man. Logically, the rational man would choose to defend the commonwealth since not to do so would be to put their self preservation at risk. The first Law of Nature states "That every man, ought to endeavor Peace, as far as he has hope in obtaining it; and when he cannot obtain it, that he may seek, and use, all helps, and advantages of Warre" (190). Man in seeking peace makes a covenant with his fellow man to set up a sovereign. There can be no covenants between sovereigns, because there is no power to enforce a covenant. Therefore all sovereigns are in a state of war with each other. If a citizen wishes peace he must defend the commonwealth "otherwise the institution of the commonwealth, which they have not the purpose to preserve was in vain" (270), and we are all in the State of War.
. . .no man can serve both Locke and Hegel. Nobody can claim to offer an "empirical" account of something called "the inclusive integrity of 'experience,'" nor take this "integrated unity as the starting point of philosophic thought," if he also agrees with Hegel that the starting point of philosophic thought is bound to be the dialectical situation in which one finds oneself caught in one's own time. (Rorty, Richard, Qtd. in Cahn, New Studies in the Philosophy of John Dewey. Hanover, N.H.: University Press of New England, 1977, P. 81)