At the same time the success of responsible government in the Colonies is, on closer examination, by no means without bearing on the problem of Ireland.  That system of Colonial responsible government which seems to us so simple and obvious is, on the contrary, one of the most artificial systems the world has ever known, based as it is upon conditions which have never been present before in the world’s history, and which are now rapidly disappearing, never, perhaps, to recur.  That a popular assembly in complete control of the executive, should respect an unwritten convention limiting its powers and rights to purely local affairs, and submit to a purely external control of its wider interests and destinies, seemed to most of Lord Durham’s contemporaries almost unthinkable.  Not only those who opposed the policy, but many of those who advocated it, were convinced that it would lead to complete separation.  Nor were their fears or hopes by any means ill-grounded.  That they were not justified by the event was due to an altogether exceptional combination of factors.  The first of these was the overwhelming supremacy of the United Kingdom in commerce and naval power, and its practical monopoly of political influence in the outer world.  Sheltered by an invincible navy, far removed from the sound of international conflict, the Colonies had no practical motive for concerning themselves with foreign affairs, or with any but purely local measures of defence.  Even when, as in 1854, they were technically involved by the United Kingdom in war with a great Power, they were not so much as inconvenienced.  The United Kingdom, on the other hand, incurred no serious expenditure for their defence beyond what was in any case required for the defence of its sea-borne commerce, nor was its foreign policy at any time seriously deflected by regard for Colonial considerations.  Even when the Colonies encroached on the original limits set them, and began to establish protectionist tariffs against the Mother Country, British manufacturers could afford to disregard a handicap of which they were at first scarcely sensible, while British statesmen smiled condescendingly at the harmless aberrations of Colonial inexperience.  Another factor was the very fact that it was colonies that the United Kingdom was dealing with, new countries where every other interest was secondary to that of opening up and developing the untamed wilderness, to creating the material framework which, in fulness of time, might support a complete national life.  There was consequently little real interest in external policy in the Colonial assemblies, little leisure for criticism of the Imperial authorities, little desire to assert any particular point of view.  Last, but not least, was the factor of distance, interposing a veil of obscurity between the different communities in the Empire; mitigating minor causes of friction, keeping Colonial politics free from being entangled in the British Party system.