According to the reconstruction that seems to best match the archeological record, Custer dispatched two companies down Medicine Tail Coulee with orders to feint at crossing the ford there, presumably to reduce the pressure on Reno by drawing more warriors north to protect their village. At the same time Custer moved north with the main body to higher ground on what later became known as Calhoun Hill, where the three companies dismounted and deployed skirmish lines to defend against mounting hostile pressure. They remained there for some time, apparently waiting the arrival of Benteen’s battalion and the reserve ammunition packs. When the two companies rejoined the main body after their demonstration at the Medicine Tail ford, Custer himself led one or both farther north looking for another ford downstream. By the time he returned from that reconnaissance, the situation of the stationary companies was rapidly deteriorating as more than a thousand Indians closed on the 210 defenders from the east, south and west of their position. Gradually at first and then very suddenly the companies collapsed like dominoes, the survivors retreating to their final position on Last Stand Hill.
Taken together those decisions make no sense. Recognizing that Reno was in trouble, a prudent commander might have ridden south to regroup and concentrate his force. An aggressive commander, intent on regaining the initiative by seizing enough hostages to force an end to the fight, would have continued north in pursuit of the fleeing villagers. In neither case would he have sat still, burning daylight as the fugitives got farther and farther away and the warriors gathered on his flanks.
The strength of cavalry is in its ability to move fast, maneuver quickly and strike hard. A static cavalry troop was no more than an under-strength infantry company burdened by a herd of nervous horses. No man knew that better than George Armstrong Custer.
Tracking Nana 