To fully understand the politics of a setting, one must also understand warfare. For now, I’m not going to address space-based combat—though I’ll have to eventually. Here are some notes upon the general nature of modern warfare in this setting:
Large-scale battles are a rarity, but they do exist. Because of the privatization of military resources, warfare in the common sense of the term only occurs when there are broad-scale clashes between high-tier associations and/or powerful corporations that have not been resolved by diplomatic measures or arbitration. Most often, large-scale warfare occurs when one or more parties attempts to resist abiding by their contractual agreements and refuses to accept arbitration of differences.
Instead, asymmetric warfare is the order of the day. Mass communication networks and the prevalence of virtual reality interfaces mean that anyone with determination, time and access can learn combat skills individually—anyone can become a trained soldier or killer. Meanwhile, body augmentation allows for individuals to become capable of exceptional physical and mental feats without the dedication necessary for grueling athletic training.
Autonomous manufacturing resources allow the untraceable (or at least not-easily-traceable) production of weapons, armor and militarized devices. The tiered-system of communities makes the regulation of such items difficult at best. Even anti-proliferation of weapons of mass destruction seems almost a lost cause, with humans’ best solace the fact that the diaspora amongst the stars makes extinction of the entire human race through warfare or weaponry extremely unlikely.
This means that small, motivated groups have all the tools they need to become effective fighters on a small scale. This is true of regular citizens with above-board defensive interests, criminal organizations, terrorist groups, and communities built around militaristic principles.
Thus, skirmishes and small-scale actions between highly-trained and well equipped teams are far more common than wholesale warfare.
This style of combat lends itself to operations that would have fallen to “special operations soldiers” in the 20th and 21st centuries. The limited resources (all considered) of smaller teams of operators influence mission types, which are more often focused on strategic, infrastructure, economic or political targets over “take & hold” missions that require large groups of infantry and other personnel to maintain. Quick, surgical strikes and terrorist-style attacks are unfortunately common, as these allow even the smallest of communities to influence sociopolitics without having to secure the support of their higher-tier patrons.
Informatics and informational warfare are of course key. Ubiquitous connectivity incentivizes hacking attacks as much as more traditionally-combative ones—though it is increasingly the case that information warfare has become in inseparable part of tactical operations rather than an independent means of warfare.
As with all asymmetric warfare, identification of combatants and non-combatants is a constant issue. Despite the use of special tactics and technologies, innocent bystanders are common victims of the disputes—ideological, political, economic—between small and self-contained tactical teams composed of individuals armed-to-the-teeth.
Despite heightened awareness of the psychological maladies that stem from participation in combat and new treatment techniques, post-traumatic stress disorder and related conditions remain a constant personal and social issue. Psychologists attribute this in part to empathic atrophy caused by the overuse of technological communication over interpersonal, face-to-face encounters, but also by the fact that many who learn their combative skills do so through games and simulations that allow for training in the physical methodologies of combat without preparing participants for the psychic stress of walking the edge between life and death and the taking of human lives.
Even though most military encounters are fought by small groups of people—often between four and thirty to a side—combined arms tactics and strategies remain at the forefront of the most effective warfare techniques. The use of semi-autonomous robots, such as drones, computerized artillery, and adaptive vehicles gives tactical teams opportunities to use combined-arms resources even on small scales with requiring the dedication to a large number of people to control those aspects of the fight. A single operator assigned toward informatics and hacking needs and a second set to supervise and coordinate the operation of drones and other automata is often enough to allow the rest of the team to focus on taking the fight directly to the enemy.