When humanity came onto the galactic stage, they quickly realized they were outclassed. With the currently insurmountable Turian hierarchy on one side, a lawless Attican traverse on the other and the Batarian Hegemony past that, the galaxy did not seem a friendly or welcoming place. A unified doctrine of war was seen as essential for the preservation and continued growth of humanity.
The alliance, grasping the reality of things, quickly realized that they could not under any circumstances get into an attritional war. A war with the council races was stupid on the face of it, but an attritional war would be lunacy. Any council race had an unbeatable edge in manpower, resources, and space. Even the Batarians had more of these vital resources than the fledgling humanity as they had been a spacefaring species for centuries before humanity came onto the picture. A defensive doctrine focused on attritional war was seen by the Alliance as a slow and sure way of suffering a grinding defeat.
The Alliance decided to focus on offense with the goal of ending any war quickly. The goal of any Alliance military operation is to destroy the enemies war making potential as fast as possible. This means hunting down and destroying the enemy fleet is the first priority. The second is to destroy infrastructure that can be used to prolong the war, the chief concerns being shipyards, comm buoys, fuel stations and refineries. Third was a halt to civilian shipping and transport. With vessels from neutral nations being turned away while vessels from the hostile power being captured or destroyed. The goal is to cause enough damage fast enough that the hostile nation would be forced to sue for peace before their superiority in in resources and manpower could come into play.
With the offensive being the key to victory it is vital in the Alliance's eyes to attack first. They dare not let the initiative be seized by the enemy. The doctrine calls to use defeat in detail should the enemy try to individually protect every world. A large overwhelming fleet going from system to system destroying the smaller piecemeal forces guarding each system. If the enemy should consolidate forces, then the choice is either for the Alliance to marshal all its strength for a grand decisive battle if it looks winnable. Some alien analysts decry the risk of such a tactic, the Alliance however sees it as necessary. They whole war is to be won or lost in a few months; they cannot let it go on for long periods. If the enemy fleet seems unbeatable then the Alliance is called on to enact a 'scorched space' policy on the undefended regions. Destroying anything of military value without getting bogged down into planetary sieges.
The Alliance defensive doctrine is largely seen as a tacked-on afterthought. Small garrisons are placed on worlds in the hope they can last long enough for an overwhelming fleet stationed at one of the various relay nexuses to counterattack the attackers. The most important Nexus being at Arcturus. Alliance colonies and Earth nations enjoy a large degree of autonomy and are allowed and expected to maintain a standing army. These vary is quantity and quality from thousands of professional soldiers, to a few hundred colonial militia. However, in event of attack they are an indispensable part of the defense.
In space battles the Alliance prefers having fighter superiority. This is achieved through carriers and an overall much larger investment in pilot training and fighter craft. Attacks are to be carried out from multiple directions. In such a way that enemy forces are forced to divert attention between multiple directions, while stray shots don't accidentally hit friendly units.
The Alliance was the first nation to deploy fighter carriers and is the only one to have them form a significant portion of their military might. Since their fighters are a larger part of their fighting power, pilot training is much more rigorous and thorough than other species, with Alliance pilots generally being regarded as the best in the galaxy. This includes pilots for capitol ships, and frigates as well as fighters. In general, the alliance chooses to focus on quality as trying to win via quantity is seen as impossible. As such training in general is exhaustive especially for any specialist roles. All members of the military receive a standard genetic therapy for improved strength and stamina, as well as to remove any sort of genetic defect such as short-sightedness. Due to manpower limits the alliance makes heavy use of drones, Vis, Artillery, space and air support.
Biotics are seen as the future of ground warfare and extensive efforts are taken to utilize the large biotic potential of humanity. Large bonuses are offered to any marine who has some potential and chooses to undergo the surgeries and laborious training required to become one. The extremely rare natural biotics are almost always pushed into special forces and are offered every opportunity to better their skills.
In recent years analysts have begun to wonder if the alliance should reconsider their doctrine. The Alliances is currently the fourth largest single economy and military power in the galaxy (It is still behind the batarians population wise but that is also growing spectacularly fast). People are wondering if the alliance should take a more balanced view on warfare. The Alliance's answer is concise "If we are fighting a foe that is weaker than us then they will not be able to withstand our offensives. If we are fighting a foe stronger than us then our only chance for victory lies in attack."
Quotes on the Alliance style of war.
"Two words, Maneuver. Warfare." Admiral Tanaka
"The Alliance always attacks!" Admiral Mikhailovich
"Every Alliance Marine! Sailor! Pilot! and Serviceman! Must be equal to five of any other as those are the odds we face!" Every single Alliance drill sergeant
"Our style of warfare is not due to any innate aggression but a simple logical response to the circumstances we find ourselves in." Admiral Hackett
"Focus on quality, victory through quantity is not an option." Prime Minister Adhiban
Aythor's Notes:
I always thought it made sense for the Alliance to be a hyperaggressive attacker since they can't win via defense. They would simply be ground down. They simply don't have the resources for it as they have only been in the galaxy for 26 years. It's a lot longer in my fanfic but still far shorter than other species. I also want it to be clear that the alliance isn't a great power. It's a regional power on the path to becoming a great power. It still has a long way to go. The gap between fourth and third place is several orders of magnitude greater than the gap between fifth and fourth.
If you're wondering about 'Natural biotics' then it is explained in the chapter 3 AN of "The bloody Path to the Stars" It will also be explained in the story I am currently writing but not in AN format.
Also, alliance is fourth largest economy because the volus are counted as part of the turian economy. This is because they are a client race.