It is, for instance, evident that, politically, one may more readily thus abandon hostile country than uncover one's own territory--as in Natal--even though the military conditions in the two cases be identical.

But, under different circumstances of position or of numbers, such dilatory field operations may be impracticable.

If the country through which retreat is to be made be open, if numbers be so small that the enemy can overlap--that is outflank--if the ground does not afford positions where the flanks may be protected by natural obstacles that make outflanking impossible or exceedingly arduous, if the enemy be greatly superior in mobility, in such conditions retreat from each successive stand is apt to be precipitate--dependent less upon one's own will than upon the enemy's energy--and the retiring army may reach its ultimate goal under an accumulation of retrograde impulse not far distinguishable from rout, deteriorated in _morale_ and diminished in numbers.
Where such unfavourable conditions obtain, the principle which dominates all correct defensive action {p.186} receives a special application.

The principle is that every defensive disposition should look to offensive action--or at the least to offensive effect.

Mere defence is ultimate ruin.