Let's take a new look at the Battle of Little Bighorn, but from the vantage point of a prospective Intelligence Officer, had there been such a thing at the time. For practical purposes, the functions of Operations and Intelligence were combined under the Commander of the 7th Cavalry, LTC Custer. So this is an examination of what his intelligence considerations might or should have been at the time. We will avoid speculation as much as possible and instead rely on decisions that LTC Custer made as well as the actions he took on the battlefield in order to understand the use of information by his Command during the battle.
Custer did have some past experience with fighting Indians on the Plains and he was successful. In particular, it is now widely agreed that his maneuver strategy focused on capturing a good portion of the noncombatants in order to bring any battle to a quick, and as possible, nonviolent conclusion as possible so that his mission of moving the tribes back to the reservations could be accomplished. We should expect also that Custer understood the way that the Indians fought. Their leadership was not as hierarchical as that of the US Cavalry, and rather their movements could be predicted to swarm, stalk, and surround if possible so that their numbers could be brought to bear in close combat. Until that critical point, they might be held at bay by accurate and sufficient (group) fire of the US Army-issued Springfield Carbines--effective over the Indian weapons at ranges between 400 (when fired in volley)-200 meters. At distances approaching 100 meters, the Indian swarming tactics and weapons could overwhelm the US advantages in range and "settle" the fight very quickly. The Indians knew this and the US forces knew this fact. For a good description of the maneuver of the battle, please refer to the YouTube site, CusterApollo - YouTube. I will tend to disagree with that author's conclusions and inferences, although I am not in dispute with his presentation of the maneuver during the battle, which I think is the best description I have come across.
It is apparent from the descriptions of Custer's movements on the battlefield that he habitually used the technique of reconnaissance by fire in order to determine the strength and proximity of enemy forces. We see this technique both at Ford B and Ford D. If the enemy tends to swarm in a non-hierarchal manner on contact, then this appears to me to be an excellent means to fix the enemy and to assess his strength. I suspect that Custer employed the same technique when he divided his forces--giving Benteen and Reno an equal three companies each to explore the approaches to the Little Bighorn battlefield and into and along the Little Bighorn valley. In other words, Custer was sincere in directing Benteen to bring to contact any forces in the folds of the ridges on the "scout to the left" and for Reno to engage the enemy along the river. The idea would be to have the enemy, if they were present, to swarm to the point of engagement. At the same time, since Indian encampments tend to be by creeks and rivers, Benteen's scout would ensure that the pack train would not be ambushed enroute. Meanwhile, Custer's strike group of five companies would maneuver along the bluff-side of the river where he did not expect a large enemy presence.
The point of the combined maneuvers would be to separate the combatants from the noncombatants and to expose the noncombatants to Custer's strike group. While, Custer knew that Reno would make enemy contact, he could not know if Benteen would encounter the enemy. However, Custer would become aware of this if an engagement developed along Benteen's path (the gunfire would be heard), and also would be able to confirm a lack of contact if Benteen fell back enroute along the main axis of advance--I suspect this was the task of Boston Custer. It appears that Boston Custer detached himself from the pack train and galloped to inform Custer at about the same time that Benteen's battalion would have appeared back in view. By the time Custer reached Weir point, he knew that Reno was engaged and Benteen was not--therefore back in the vicinity of the packs. His order to Benteen confirmed that knowledge.
The reason for having Benteen and the pack train hurry forward was that the location of the Indian village was now confirmed and that it was known to be concentrated at that location--thus there was no need to explore further. Also, Reno was engaged and the swarm of Indians would be building against him--it was not that Custer needed immediate help. At the time Custer sent the messages, he was attempting to manage a reconnaissance, not to attack. The enemy was not in contact with him at the time, except for the activity taking place as a result of Reno's attack. Custer did not know at that time that the enemy forces would overwhelm Reno, and if they did, we should expect that his orders to Benteen were to give the promised support as Benteen came up along the axis of advance. The flow of US forces in the assault followed South-North and would flow North to South along the river if in retreat. Thus, Benteen could not avoid rolling up upon Reno if the Reno engagement battle traveled southward (in retreat).
Certainly, Benteen was not expected to leave a beleaguered Reno to fight alone against a far superior Indian swarm. Why do historians even assume this would enter Custer's mind? Or be assumed by Benteen? That thought is absurd. Nor should anyone assume that Custer would not support Reno as promised or that Custer was so cold to the fate of Reno's battalion as to give no concern for the outcome of the engagement. Reno's mission was to stir up an Indian swarm, not to overrun them if they were superior in force. Reno did what was expected of him and Custer was apparently satisfied with the way that Reno was deploying his forces, otherwise, he could easily have sent an alternative order to Benteen to support Reno's attack rather than to simply "Come on and be quick". The fact that Benteen would do what was feasible and best was assumed. He was a seasoned veteran and would not have been entrusted with a battalion otherwise; likewise Reno.
The subtext of this "reconnaissance by fire" approach is that the elements that make contact are unknowing pawns to a certain degree. They should attract a swarming enemy, but be sufficient enough so that they hold that contact without collapsing while the maneuver elements either come to their support (if the enemy strength is too much), or can locate and attack the separated noncombatants (ideally). Thus, Custer told Reno that Reno would be supported, but not much more. I believe Custer's movement to Ford B was an attempt to support Reno as necessary and in any case to determine the effect of the Reno's assault. However, by that time Reno was routed back to Reno Hill and not to be found. The enemy forces were simply too large and too aggressive. This was the singular surprise that Custer should have better considered, but underestimated even beyond the allowances of his tactics.
The surprising thing about the Reno engagement, I expect, was not that Reno was forced into retreat, but rather that Reno was able to break contact and find a defensible location, whereupon it was the enemy that broke contact. It is ironic that Custer’s appearance at Ford B was most likely the reason that the Indian swarm broke contact with Reno. Custer's strike group was maneuvered to shield it as much as possible from enemy observation except for this one instance up to that point of the battle.
The fact that the Indians became aware of his group and quickly reoriented on it appears to have not been Custer's plan. However, I believe that Custer made provisions to become aware of this possibility in that he continuously positioned Keogh's wing of the strike group to act as a rearguard as Custer led E and F companies in a probe in the Ford B and D areas. Custer was positioning himself to either support or attack dependent on his own assessment of the situation at the point of own probes. This is not a bad idea. In maneuver warfare, the situation changes very dynamically and the right decision at the right point with the right force is what changes the battle. Custer was a demonstrated expert in this aspect of warfare.
By the lack of enemy in the Ford B area, Custer would know that Reno was routed (or annihilated) back towards the South and that the largest portion of the enemy was in that proximity as well. However, with Benteen coming up, there was a question of whether Benteen and the pack train (which were to be guarded under Benteen's battalion and not left behind), would reach either Reno or Keogh. Custer needed a signal whether friendly of enemy forces reached Keogh first. If the enemy, Custer would know that Benteen was either stuck supporting Reno, or perhaps defeated as well. If Benteen somehow made it to Keogh, the assumption would have to be that either Reno had fled the field or that his command was annihilated, because he certainly was nowhere in the vicinity of Ford B as Custer determined himself.
The volleys were that signal--apparently two volleys meant that the enemy had arrived first to the Keogh rearguard position on Luce ridge (which made sense--why waste ammunition on signaling if those two volleys could be put to effect against the enemy? we should suppose that one volley would mean that Benteen arrived). Upon this signal, Custer withdrew from his probe at Ford B and rejoined Keogh, then moved together further north to Calhoun Hill where Keogh was again reestablished in a rearguard position. There was no attempt to further support or rescue Benteen/Reno. Whatever time that existed for that group to engage and fix the enemy was now running out.
Custer still had five companies to his knowledge and perhaps still some chance to bring the battle to a conclusion if he could capture the noncombatants. The hope would have been that Reno/Benteen's fight engaged enough enemy warriors that the noncombatants were relatively undefended. This would also mean that Benteen and the rest of the Regiment would not be seen anytime soon if at all. The signal of the volleys was for Custer--not for Benteen. Why have a signal that is not prearranged? Custer intended for Benteen and Reno to be probes---not the maneuvering element. They were the pawns just as Sturgis was at Ford B and Yates at Ford D.
Benteen and Reno did exactly what Custer had wanted them to do, according to this understanding of information flow on the battlefield. There is absolutely no reason for the recriminations. When Custer heard the volleys, he knew that a force strong enough to defeat Reno and to deter Benteen was falling on Keough (at perhaps 400m) and that Keough had little time to spare. In fact, Custer's time was up as well. With either insufficient force at Ford B, a lack of noncombatants, and no Reno, the only hope was to intercept the noncombatants further north. It was never in the plan to fight through to Reno/Benteen and to admit defeat. Reno/Benteen were sacrificial pawns if necessary. The only force that must be preserved was the strike group.
The battle was concluded when although Ford D and the noncombatants were found, Keogh's wing was obliterated so there was insufficient force to overcome what defenses existed at Ford D and consummate the attack on and seizure of the noncombatants. Apparently, Custer suffered from some period of indecision as the Keogh wing of the strike group was being obliterated and Custer neither came to their support nor committed to the strike against the noncombatants at Ford D. I suspect that the idea of saving the two companies and Regimental headquarters by fleeing the battlefield to unite with Terry must have occurred but was decided against. Custer's group stood together and fought together until the end. If the group that tried to break out from last stand hill was that remnant that wanted to flee to Terry, they had already done their duty by that time and might as well have tried. The enemy forces were simply too strong, and Custer had split his own forces too much. In fact, apparently the enemy defenses in the Ford D area were tried twice and each time they were found to be too strong to launch the seizure attempt. While the plan to separate the combatants largely from the noncombatants worked, the force imbalance was too much to maintain this separation and to make a successful seizure.
There is no purpose in capturing noncombatants if only two companies of your entire Command are left and the rest wiped out. Custer knew that the swarm that fell upon Reno was falling upon the equally sized Keogh force. The only honorable thing to do would be to stand with the remnants of the Command and perhaps save the Regimental colors. And after the desultory attacks at Ford D, that is what Custer did. Furthermore, it should be noted that Custer's note to Benteen is generally interpreted as a cry for help by Custer to aid Custer. This assumes far too much. The only presumption we should make is that it is the final and termination of a series of orders directing Benteen's "scout to the left" and that it emphasized that the Pack Train was now Benteen's (and no one else's) responsibility to bring ahead. Benteen did not have reason to assume that he should come ahead either by the bluffs or the valley until he himself witnessed Reno's forces scrambling to the bluffs. As far as Benteen knew at the time, the fight could be in the valley, not the bluffs regardless of which direction Custer's strike force took after Ford A. Afterall, Custer might have crossed by that time at Ford B had either the Reno or Indian situation developed other than it did.
The entire US 7th Cavalry acted honorably. The enemy force was simply several times larger and fought with much more zeal than the US Military's best estimate. The 7th Cavalry was lucky that some of its companies escaped--but this was primarily due to the leadership of Reno in the timbers in making a timely escape and in Benteen in formulating the defense of Reno-Benteen Hill. It was never intended that Benteen would come to Custer's aide if Reno was defeated. Either Benteen would be aiding Reno or fighting the large body of enemy that had defeated Reno. I believe this was part of Custer's plan and that it was not communicated to Reno and Benteen in advance, because of the unfortunate side-effect of being absolutely demoralizing had they had known that it was necessary for them to be the potentially sacrificial pawns.
What went wrong? Custer's force should have been a reconnaissance and blocking force, not the strike group. There should have been no attack of any magnitude until Terry was on the field. Therefore, IMHO, the fault lies with the overall plan of the campaign. Given the task to act as a strike group, Custer, to the best of his knowledge, acted as a strike group. If we must criticize, then the only clear action that I can see is that Custer should have better perceived the impact of a large dynamic enemy on his initial plan from his observation at Weir point. This meant that he had only one chance to “get it right” and so rather than attempting an attack as close as Ford B, he should have gone straight into an attack at Ford D with all five companies and go for broke. In other words, he did not have the luxury to be cautious or incremental.
As a final note, I believe that the Indians far understated their own causalities, which probably approached 600. There was a tendency for some Indians to claim that large numbers of the 7th committed suicide, where the evidence strongly speaks to the opposite--that the wounded were murdered by the Indians. This should not be forgotten or forgiven as a cultural consideration. The wanton and intentional murder of those who are either noncombatants or hors de combat, is fundamentally evil to any coherent morality. A culture that refuses to extend mercy and compassion to the helpless is not a culture that by its own measure can exist peacefully with others. This lesson, thankfully, did finally prevail. Legitimate land disputes should be settled peacefully. It is only dust and a way of life is only a way of life when it involves living. Otherwise, it is a way of death. Had the mission of the 7th Cavalry been that of the Indians, there would be no historical need for an elaborate analysis of maneuver or information.