“The possession of strategic points,” says the Archduke Charles, “is decisive in military operations; and the most efficacious means should, therefore, be employed to defend points whose preservation is the country’s safeguard.  This object is accomplished by fortifications, inasmuch as they can resist, for a given time, with a small number of troops, every effort of a much larger force; fortifications should, therefore, be regarded as the basis of a good system of defence.”  “It should be a maxim of state policy in every country, to fortify, in time of peace, all such points, and to arrange them with great care, so that they can be defended by a small number of troops.  For the enemy, knowing the difficulty of getting possession of these works, will look twice before he involves himself in a war.”  “Establishments which can secure strategic advantages are not the works of a moment; they require time and labor.  He who has the direction of the military forces of a state, should, in time of peace, prepare for war.”  “The proper application or neglect of these principles will decide the safety or the ruin of the state.”  “Fortifications arrest the enemy in the pursuit of his object, and direct his movements on less important points;—­he must either force these fortified lines, or else hazard enterprises upon lines which offer only disadvantages.  In fine, a country secured by a system of defences truly strategic, has no cause to fear either the invasion or the yoke of the enemy; for he can advance to the interior of the country only through great trouble and ruinous efforts.  Of course, lines of fortifications thus arranged cannot shelter a state against all reverses; but these reverses will not, in this case, be attended by total ruin; for they cannot take from the state the means nor the time for collecting new forces; nor can they ever reduce it to the cruel alternative of submission or destruction.”

“Fortifications,” says Jomini, “fulfil two objects of capital importance,—­1st.  The protection of the frontiers; and 2d.  Assisting the operations of the army in the field.”  “Every part of the frontiers of a state should be secured by one or two great places of refuge, secondary places, and even small posts for facilitating the active operations of the armies.  Cities girt with walls and slight ditches may often be of great utility in the interior of a country, as places of deposit, where stores, magazines, hospitals, &c., may be sheltered from the incursions of the enemy’s light troops.  These works are more especially valuable where such stores, in order not to weaken the regular army by detachments, are intrusted to the care of raw and militia forces.”  It is not supposed that any system of fortifications can hermetically close a frontier; “but, although they of themselves can rarely present an absolute obstacle to the advance of the hostile army, yet it is indisputable that they straiten its movements, change the direction of its marches, and force it into detachments; while, on the contrary, they afford all the opposite advantages to the defensive army; they protect its marches, favor its debouches, cover its magazines, its flanks, and its movements, and finally furnish it with a place of refuge in time of need.”