Solomani Confederation Mobile Corps
As anyone would have guessed by now , the Motorized Battalions were originally intended to provide locally cannon fodder for the Solomani Army for security or low intensity conflicts. I couldn't resist adding in elements from other games and/or settings, the more i thought about expanding the concept.
As such, it sort of evolved/evolving.
The ULTRAMarines were supposed to be the equivalent for the Solomani Navy, for ground operations, to be led by promising Marine NCOs and junior officers, and structured to not require a mandatory SolSec liaison. They were, of course, based on the United States Colonial Marine Corps from Aliens, which is why they were equipped with ACRs, and partially as a joke on Forty Kay's Ultramarines.
They've since been amalgamated with the Motorized Corps, to give the cannon fodder a path to a career if they are competent and lucky enough to survive, as well as provide the Solomani military with more professional units and cadre for the newly recruited units.
Continuing with the Forty Kay theme, though looking like Sardaukar from the Dune movie, justified on the grounds that Combat Armour, let alone Battle Dress, just would be considered too expensive for expendable troops, we have the veteran TERMINATOR troops, who generally can hit what they shoot at, and get the most advanced variant of slug thrower weaponry available.
The Star Wars Imperial Army gets involved with the concept of augmentation, which at this point meant I considered making the Motorized Corps more widespread and possibly self contained, though their primary function is to support the Stormtrooper Corps (Confederation Marines), and the Solomani Army, who in my view, would be almost entirely mechanized, and highly technical, which is why they needed cannon fodder to provide a personal presence on the field. In either case, both the Army and Marines would have had their choice of recruits, but would have size constraints, so they picked the best. The Motorized Corps allows those disappointed but still enthusiastic for a Confederation military career outside of the Home Guard, to have one.
In theory, the Home Guard is supposed to be a planetary reserve militia, which begs the question, do member worlds have a professional military? Considering some of the ambitious ones mentioned, very likely, otherwise how do they plan to project their power and create a sphere of influence? But that's probably a topic for another day.
Overall, Pournelle's influence should be remarked on, even if it wouldn't be obviously so. At the lowest end, troops are issued with an autorifle, which can outrange an assault rifle, and remains at least in parity until the introduction of ACRs, which are likely to be similar to Judge Dredd's Lawgiver in that they have effective user recognition biometric guards that prevent unauthorized ones from being able to use them. While mileage will vary, it seems likely that Confederation subpolities will designate them as military hardware and restrict them. So you can neither collect nor hunt with them.
Note that I've changed the name from Motorized to Mobile, as a nod to the film.
