An argument for the pace and not the cubit

[Densus]

Adam,

Thank you for your knowledgeable posts. The formation order you describe as the most efficient, with 6 inch gaps between shields, seems to be similar to the spacing of Vegetius' 30 inches per man. However, I have a few questions. You mention that the rioters would be able to get through the gaps of a wide open formation, like the Polybian version. if the riot police were attacking/charging instead of remaining stationary or advancing slowly and cautionary, would this change matters? What is normal protocal for breaking a crowd of rioters? Wait them out or a concerted and violent attack in the beginning?
(from your posts I assume you actually are a police officer training/deploying in these formations, pardon me if am wrong)

The short version is that in the system we use/teach if we are going forward we are in open order (an arm, a baton and six inches), if we are standing still or moving backwards we are in cordon (shields touching). That isn't a hard and fast rule because it is situation dependant but that is the norm.

There is no normal protocol for dealing with rioters because every situation is so different and there are a lot of quite subtle issues that need to be taken into account.

I am not a police officer, I am a former Army officer but I spent most of my career in Northern Ireland supporting the police on these type of operations. I now teach public order internationally.

From this passage, among many other examples available, I think it seems pretty clear, at least in reference to this late Republican time period, that a key element of an attack would be an aggressive charge. I just don't see how a force of infantry armed as the Romans were can charge (run) forward in a close order arrayed formation that allows close to zero room to maneuver, ie. maintaining shield to shield touching intervals, with zero gaps as in a "hinged phalanx." It might work if the force remains stationary or advances at a slow walk or drag step, over an short distance in good terrain, but the Roman advance described by Caesar reads a lot less like a slow and methodical Spartan or Macedonian advance, as compared to a wild Gallic charge. Wild and disordered enough that, halfway through the charge, it became necessary for Caesar's cohorts, filled with veterans of countless battles (so inexperience can't be the reasoning), to stop and reform/reorganize, before again advancing/charging.

Also, how well "drilled" were Caesar's men, since it meant after advancing a short distance, while not in contact with the enemy, they became as disordered as they did? Were they poorly drilled because that short distance destroyed their cohesion, forcing them to have to stop and reorganize? Or were they well drilled because they took initiative to stop and reform on their own before continuing their advance, without needing orders from legates or Caesar himself?
Either way, Frederick the Great would have mortified...

You would be surprised how quickly even a well trained unit can lose cohesion once you start advancing at any thing faster than a walking pace, especially over broken ground. To counter that we try to keep bounds down to about twenty metres.