"The supreme interest," he said, "ties in the physical fact that it (the northwestern frontier) is the only side upon which India has been or ever can be invaded by land, and in the political fact that it confronts a series of territories inhabited by wild and turbulent, by independent or semi-independent tribes, behind whom looms the grim figure of Russia, daily advancing into clearer outline from the opposite or northwest quarter. It is to protect the Indian Empire, its peoples, its trades, its laboriously established government and its accumulated wealth from the insecurity and possible danger arising from a further Russian advance across the intervening space that the frontier which I am about to describe has been traced and fortified. Politicians of all parties have agreed that, while the territorial aggrandizement of Russia is permissible over regions where she replaces barbarism even by a crude civilization, there can be no excuse for allowing her to take up a position in territories acknowledging our sway, where she can directly menace British interests in India, or indirectly impose an excessive strain upon the resources and the armed strength of our eastern dominions. The guardianship of the frontier is, therefore, an act of defense, not of defiance, and is an elementary and essential obligation of imperial statesmanship. "Originally it was supposed that there were but three or four passes or cracks by which this mountain barrier was perforated, and that if British soldiers only stood sentinel at their exits an invader would have no other alternative but to come down and be annihilated. Modern surveys, however, have shown that the number of available passes is nearer 300 than three, a discovery which has suggested the policy of establishing friendly relations with the tribes who hold them, and thus acquiring an indirect control over their western mouths. For just as the main physical feature of the frontier is this mountain wall, with its narrow lateral slits, so the main political feature is the existence in the tracts of country thus characterized of a succession of wild and warlike tribes, owing allegiance to no foreign potentate, but cherishing an immemorial love for freedom and their native hills."