But further, as we saw, it is not so easy to say what the established government is. For sometimes an authority declared by law to be illegitimate issues ordinances and controls the administration of justice. The question then arises, how far obedience is due to such an authority. All are agreed that usurpation ought to be resisted; but as to the right behaviour towards an established government which has sprung from a successful usurpation, there is a great difference of opinion. Some think that it should be regarded as legitimate, as soon as it is firmly established: others that it ought to be obeyed at once, but under protest, with the purpose of renewing the conflict on a favourable opportunity: others think that this latter is the right attitude at first, but that a usurping government, when firmly established, loses its illegitimacy gradually, and that it becomes, after a while, as criminal to rebel against it as it was originally to establish it. And this last seems, on the whole, the view of Common Sense; but the point at which the metamorphosis is thought to take place can hardly be determined otherwise than by considerations of expediency. But again, it is only in the case of an absolute government, where customary obedience is unconditionally due to one or more persons, that the fundamental difficulties of ascertaining the legitimacy of authority are of the simple kind just discussed. In a constitutionally governed state numerous other moral disagreements arise. For, in such a state, while it is of course held that the sovereign is morally bound to conform to the constitution,[232] it is still disputed whether the subjects’ obligation to obedience is properly conceived as conditional upon this conformity: and whether they have the moral right (1) to refuse obedience to an unconstitutional command; and (2) even to inflict on the sovereign the penalty of rebellion for violating the constitution. Again, in determining what the constitutional obligations really are we find much perplexity and disagreement, not merely as to the exact ascertainment of the relevant historical facts but as to the principles on which these facts ought to be treated. For the various limitations of sovereign authority comprised in the constitution have often been originally concessions extorted by fear from a sovereign previously absolute; and it is doubted how far such concessions are morally binding on the sovereign from whom they were wrested, and still more how far they are binding on succeeding sovereigns. Or, _vice versâ_, a people may have allowed liberties once exercised to fall into disuse; and it is doubted whether it retains the right of reclaiming them. And, generally, when a constitutional rule has to be elicited from a comparison of precedents, it is open to dispute whether a particular act of either party should be regarded as a constitutive precedent or as an illegitimate encroachment. And hence we find that,