(a) The French political frontier, as established since the defeat of the French in 1871, is an open frontier.  It has no natural features upon which the defensive can rely.  In the lack of this the French fortified at very heavy expense that portion of their frontier which faced their certain enemy, and established a line from Verdun to Belfort calculated to check the first movement of his offensive.  But all the two hundred miles to the north of this, the whole line between Verdun and the North Sea, was virtually open.  There were, indeed, certain fortified places upon that line, but they formed no consecutive system, and, as their armaments grew old, they were not brought up to date.  The truth is, that the defence of France upon this frontier was really left to the co-operation of Belgium.  If, as was believed to be almost certain, Prussian morals being what they are, the Prussian guarantee to respect Belgian neutrality would be torn up at the outbreak of war, then three great fortresses—­Liege, Namur, and Antwerp—­would hold up the enemy’s advance in this quarter, and perform the function of delay which the obsolete armament of the north-eastern French frontier could not perform.  We shall see, when we come to the conflicting theories of warfare held by the various belligerents, what a grievous miscalculation this was, and how largely it accounted for the first disasters of the war.  But, at any rate, let us remember, as our first point, the absence of any natural line of defence in France as against a German invasion, remembering, also, that the French would necessarily, at the beginning of any war, be upon the defensive on account of their inferior numbers.  Had France, for instance, had along her frontiers, and just within them, such a line as Germany possesses in the Rhine, she would have fallen back at the outset upon that line.  But she has no such advantage.

(b) The second disadvantage of the French geographically is one immixed with political considerations.  The French have for centuries produced, and have for two thousand years believed in, central government.  For at least three hundred years all the life of the nation has centred upon Paris; all the railways and all the great system of roads and most of the waterways of the north similarly have Paris for their nucleus.  Now, this central ganglion of the whole French organism is but 120 miles from the frontier, ten days’ easy marching.  An enemy coming in from the north-east not only finds no natural obstacle in his way, but has Paris as nearly within his grasp as, say, Cologne is within the grasp of a French invasion of North Germany.  This feature has had the most important consequences upon the whole of French history.  It was particularly the determining point of 1870.

To meet the handicap, the French of our generation have combined two policies.

First, they have fortified the whole region of Paris so thoroughly that it has sometimes been called “a fortified province;” an area of nearly thirty miles across at its narrowest, and of something like from seven to eight hundred square miles, is comprised within this plan.