By what principle must our choice between the two systems be determined? By the purpose in hand. The sole ultimate use of an army is to win the nation's battles, and if one system promises to fulfil that purpose while the other system does not, we cannot hesitate. Great Britain requires an army as one of the instruments of success in a modern British war, and we have therefore to ascertain, in general, the nature of a modern war, and in particular the character of such wars as Great Britain may have to wage. The distinguishing feature of the conflict between two modern great States is that it is a struggle for existence, or, at any rate, a wrestle to a fall. The mark of the modern State is that it is identified with the population which it comprises, and to such a State the name "nation" properly belongs. The French Revolution nationalised the State and in consequence nationalised war, and every modern continental State has so organized itself with a view to war that its army is equivalent to the nation in arms. The peculiar character of a British war is due to the insular character of the British State. A conflict with a great continental Power must begin with a naval struggle, which will be carried on with the utmost energy until one side or the other has established its predominance on the sea. If in this struggle the British navy is successful, the effect which can be produced on a continental State by the victorious navy will not be sufficient to cause the enemy to accept peace upon British conditions. For that purpose, it will be necessary to invade the enemy's territory and to put upon him the constraint of military defeat, and Great Britain therefore requires an army strong enough either to effect this operation or to encourage continental allies to join with it in making the attempt. In any British war, therefore, which is to be waged with prospect of success, Great Britain's battles must be fought and won on the enemy's territory and against an army raised and maintained on the modern national principle. This is the decisive consideration affecting British military policy. In case of the defeat of the British navy a continental enemy would, undoubtedly, attempt the invasion and at least the temporary conquest of Great Britain. The army required to defeat him in the United Kingdom would need to have the same strength and the same qualities as would be required to defeat him in his own territory, though, if the invasion had been preceded by naval defeat, it is very doubtful whether any military success in the United Kingdom would enable Great Britain to continue her resistance with much hope of ultimate success.