In the United States the three unit organization is most clearly marked. The division consists of three brigades, each brigade of three regiments, and each regiment of three battalions. The battalions have a strength of only 400 men. [222] _Taktik_ (_Kriegsgliederung_), III, p. 31, et seq. Base Units. The possibility of regulating the movements of a body of troops by means of a base unit, depends upon a number of preliminary conditions which will seldom be fulfilled in war: 1. _The leader of the base unit would have to remain unharmed to the very last._ If he were disabled the command of the unit would devolve upon the next in rank who would perhaps not join it in every case. 2. _The fresh organisation which imparts the impetus necessary for a further advance, would have to maintain the direction after the original base unit had ceased to exist on account of the mixing of organizations._ 3. _The base unit would have to encounter less difficulties during its advance than the other units of the force._ If the base unit were to encounter greater difficulties than the other units, this might serve as an excuse for reducing the rate of advance. In attack, the organization nearest the enemy, in other words, the one that is led better and more energetically than the others, is quite naturally charged with maintaining the direction. Moreover, this organization will be able to facilitate by its fire the advance of the elements in rear. The designation of a base unit[223] or unit of direction on the battlefield cripples the energy of an entire line and the initiative of the individual in favor of uniformity of movement. A base unit is only profitable in night operations, in crossing unfavorable ground (woods), and in bringing the fighting line up to the effective zone of hostile fire. “With the entry into action, the importance of the base company gradually decreases as the demands made by the combat increase”. (Par. 242 German I. D. R.). In all other cases, it is better to indicate either the objective on which the troops are to march, or the flank toward which they are to maintain connection. [223] “A unit may also be designated upon which the others have to regulate their movements without thereby being curbed in their endeavor to advance (base unit of combat).” (Par. 371 German I. D. R.) In France units of direction are prescribed (_la direction est confidée aux unités qui suivent les chemins ou les lignes naturelles du terrain_), but their duties are not given in detail. Units of direction are also prescribed in Austria.