Without the British Navy, in particular, the war must have collapsed in a month.
But the main brunt of the struggle on land had to be borne--and was superbly borne--by France up to the summer of 1916, when we entered on our full strength.

Thenceforward the chief strain lay on the constantly developing Armies of Great Britain.

From July, 1916, to the Armistice, Sir Douglas Haig bids us conceive the long succession of battles fought by the Allies in France as "one great and continuous engagement." "Violent crises of fighting" within such a conflict may appear individually as "indecisive battles." But the issue is all the time being slowly and inexorably decided.

And as soon as the climax is reached, and the weakening of one side or the other begins, nothing but the entry of some new and unexpected factor can avert the inevitable end.

When Russia broke down in 1917, it looked for a time as though such a new factor had appeared.