STRATEGY FOR OFFENCE
The objectives of the Systems Alliance in the Kite's Nest, and the war generally, were ambitious but entirely necessary to preserve the dignity, security and prosperity of humanity for the future. First of all, the Hegemony's naval power would need to be annihilated. Secondly, Khar'shan itself would have to be invaded and subjugated, in order to bring the whole rotten edifice of the Hegemony crashing down. Thirdly, the victory in space and the launch of the ground campaign would have to be so swift as to crush any chance of the other batarian clusters coming to aid the homeworld. Taken together, the Alliance did indeed have the capability to achieve these objectives.
Unknown to the Hegemony, and only speculated upon by human intelligence operatives, the Alliance had significant advantages in naval strength, derived mostly from the superior quality of its ships and tactics. The batarians would always outnumber the Alliance on the ground, but with space superiority, the emphasis on troop quality and the use of drones, the numbers counted for little.
The batarians possessed one supreme advantage that invalidated all of the Alliance's own, and it was rooted in the nature of galactic-scale war. A nature that is extremely difficult to overcome; it is almost impossible to launch attacks across wide fronts from one cluster to another, as relay travel is and was the only way to transit between the void of space. The relatively small jumpzones can be flooded with mines, guarded by space stations and fleets, and crowded with asteroids. Stalemates across relays could be maintained for decades, broken only by the application of brute force. This problem is at the root of why both the Rachni Wars and the Krogan Rebellions stretched into centuries-long conflicts. Both species faced by the Council in those wars were supremely adapted to attritional warfare, and yet they could not overcome this simple reality of war. On occasions where they did break relay defences, they often found their supply lines in great danger. Many lives were lost to bring the genophage to Tuchanka.
From the very beginning, the Alliance looked to humanity's own genius for innovation to try and break this reality. In the First Contact War, miming turian IFFs in the latter weeks of the conflict proved successful, until the end of the war put an end to that concept with better VI capability. At Elysium, when Combined Battlefleet Hiryu arrived through the main system relay, it was preceded by Scylla-class transrelay ballistic missiles delivering cobalt-encased thermonuclear weapons. These are designed to flood the sensors of the defending batarian ships with heat and radiation contacts like a chaff grenade. Of all techniques used to confound relay defences, this has proven the most long-lived; the higher the resolution of enemy sensors, the worse affected they are by this method. The geth would find this a particularly galling tactic during the Eden Prime War, especially combined with quarian electronic countermeasures.
However, these methods can fail and still require a crucial risk; the attacking force must still send their ships through the relay and into the tiny jumpzone on the defender's side. Even firing blind, defending forces can inflict significant casualties, particularly on cruiser-sized ships and beyond. This was why the counterattack at Elysium was headed up by frigate wolfpacks, to destabilise the batarian defences before the cruisers, carriers and dreadnoughts arrived. Frigates are small and fast enough to make lucky hits far less likely.
Consul Taro and Minister deBankole were well aware of this problem before the beginning of the Second Verge War. Their most realistic expectations as early as 2174 were that when the war came, the Alliance could push the batarians all the way back to the Kite's Nest but not follow them there by relay. When these predictions were proven absolutely correct two years later, planning for an alternative strategy had already begun.
The Verge is a wing of densely packed star clusters, of which the Kite's Nest can be considered an exclave. It had long been theorised by batarian astronomers and spaceflight experts that the Verge and the Kite's Nest could be bridged by normal FTL in as little as a year. Proposals to that effect were brought to the Citadel Council by the Hegemony in the aftermath of the Rachni Wars, but rejected. A year at FTL without shutting down the cores for maintenance was unthinkable, and the travel time would be greatly increased if stops had to be made. The idea was set aside and forgotten by almost everyone, even as advances in FTL technology shaved months off the potential travel time as the centuries went by. When the Alliance Defence Intelligence Directorate went looking for ways to bypass the defences of the Kite's Nest, it rediscovered these proposals in the Citadel public archives.
In 2175, Commander Federic Kohaku, a naval analyst with the DID, redid the calculations to account for the military FTL designs of the Alliance. The travel time from the edge of the Verge to the edge of the inhabited Kite's Nest was found to be as little as two months, provided that communications, supply and discharge sites could be established along the route. When this was reported to the Consul at a cabinet meeting, it is reported that she did nothing but smile widely for the rest of the entire session, as her ministers descended into jubilant planning. After the war began, the necessary infrastructure for bypassing the Verge Wall was already prefabricated.
Once the Hegemonic Navy had been pushed back, and it was certain that there was no way the batarians could obtain intelligence about activities, the scouting and construction of the first part of the bridge into the Kite's Nest was started. The path would come to be known as Tower Bridge, as the famous bridge in London was undergoing reconstruction at huge expense around the same time. From 2176 to 2178, the deep space squadrons roved ever forwards, connecting distant stars together in a great chain of stations and FTL comm-buoys.
The Alliance had its path into the Hegemony's core, but it also required a whole new strategy to take advantage.
The last part of Tower Bridge would have to be completed just as the Navy began its two month journey, as the nearest charted pre-war batarian outpost was two light-months from where the last refuelling, supply and comms station would have to be placed. It was entirely possible that the station could be discovered just before the Alliance Navy arrived, leading to a fight on the edges of the Kite's Nest rather than one closer to Khar'shan. It was determined that the batarian outpost would have to be taken by force, and a First Legion unit was assigned to the task along with a navy bomber squadron to make a stealthy approach.
The exit of Tower Bridge was 'north-west' of Khar'shan itself, both more or less level with the galactic plain. This left obvious two attack options for Alliance planners. They could use a smaller number of fleets to push through to the Viper Nebula relay via the secondary relay within the Harsa System itself. This would leave the defences of the Viper Nebula open to easy attack from within, opening the relay there to Alliance forces from the Traverse. These combined forces would then attack Khar'shan.
Alternatively, they could bring the majority of the Navy's fleets through Tower Bridge and attack directly, using the secondary relay's jumpzones as an ambush point against the fleets guarding the other relays of the Verge Wall. Both plans had distinct advantages, but both were flawed. Using the bridge to merely open the Viper Nebula relay route would leave the Navy to depend on the Harsa secondary relay, which could be guarded against if the batarians acted quickly and cut the route there. Bringing the majority of forces through via Tower Bridge would leave them with a very long supply line, requiring more of the vulnerable cargo vessels to be sent through with the fleets than was ideal.
By the start of 2178, the question of which strategy should be used was becoming urgent, and debate within the Navy was becoming rancorous. The Army, eager to begin its own planning for the invasion of Khar'shan itself, lost its patience, and brought a compromise forward directly to the Consuls. The three heads of the Troop Commands proposed that the middle ground was the best strategy. Bring half the fleets through Tower Bridge, which was the maximum number that could disappear for two months without raising suspicions. Have the fleets hold at Khar'shan, to divide and conquer the Hegemonic Navy. Use the deterrence frigates to destroy the fixed defences at the Viper Nebula and Yuki Cluster relays from behind, allowing passage of three more fleets into the battle. The plan would require seven out of eight combat fleets and the entirety of one part of humanity's WMD triad. In effect, the Army's plan meant going all-in.
Consul Taro approved it immediately and without hesitation.
STRATEGY FOR DEFENCE
The Hegemony's defensive strategy had two objectives: Lure the Alliance into fighting a trans-relay battle where it would be at a great disadvantage, and counterattack from the other relays as soon as possible, preferably during the Alliance attack. In destroying as much of the Alliance fleet as possible, and seizing key territory back from the humans in the process, Arch-Hegemon Ar'dra hoped at the very least to force a status quo ante bellum via a negotiated settlement. His great hope however was to break the human navy upon the rock of his defences and blitz the entire Verge into his control before the Alliance could recover. It was far from outside the realm of possibility, and Alliance analysts in the post-war period agree that had they been forced to assault the 'Verge Wall' directly, a coordinated counteroffensive could very well have accomplished many of the specific objectives that the Arch-Hegemon had in mind. However, the Alliance plan for such an eventuality was equally devastating; the nuclear holocaust of Khar'shan.
The exact planning for the one-two defence-counterattack strategy was left to Admiral Ar'dra, the same man who had been defeated over Elysium but had still managed to save a portion of the Batarian First Fleet. His cousin brought him back to organise the deployment of the Navy, a task he took to with great zeal. The Batarian First Fleet, refitted and rearmed after Elysium, would guard the Harsa-Prime relay and the Kite's Nest cluster itself. The Second Fleet would guard the Viper Nebula relay and the Bahak system. The Third Fleet would help defend the Yuki-Theta relay and the Petra-Falu relay, splitting its forces in two as these were the furthest from Khar'shan and the least likely to be used. These fleets were numbered according to their strength and the prestige of their commanders, so that the Alliance could expect the most resistance from the First Fleet and the least from the Third. At each relay jumpzone, the fleets would be aided by a large number of space-to-space weapons-stations, ranging in capability from torpedo barges to dreadnought-scale space cannons. Mines were also deployed on the Yuki-Theta relay zone, as it would not be required for the proposed counterattack.
No significant plans for defending Khar'shan or other worlds groundside were made. The assumption was made that if the Navy lost, it would be the duty of every batarian soul to throw themselves upon the enemy to remove them. This was considered absolutely enough to repel the humans should they land, as the slaughter would be so terrible that the Citadel would be forced to intervene. This is not as naïve as it may seem to present-day readers, as the Council would indeed be deeply concerned at the possibility of casualties. Anhur and Torfan would paint the probable bodycount ever higher in the minds of the greater galaxy.
The counterattack phase took into account the batarians' groundside losses. Whichever relay was the source of the Alliance attack, the other major fleet would spring into action. If the attack came at Harsa, the Second Fleet would attack out of the Viper Nebula. If the attack came against the Second Fleet, thought to be far more likely by batarian planners, the First Fleet would attack instead. If the Third Fleet was attacked at either of its minor relays, both the First and Second Fleets would attack.
The objective of the offensives would be the Exodus Cluster; Terra Nova and Eden Prime specifically. The cluster would be cut off from the rest of the galaxy, and used as a jumping off point to bombard colonies in surrounding clusters to encourage the Alliance to retreat. Ambushes would be laid at relays en route to colonies under siege, and the remaining human navy assets reduced. At this point, Admiral Ar'dra anticipated intervention by the Citadel, but continued the plan's general push to end at Sol itself.
If it had not been for the ingenuity of humanity, these plans very well could have seen some level of implementation. Their callousness is equalled by Alliance plans to counter such plans, but the ruthlessness and cunning displayed by Admiral Ar'dra is still striking today. Without the Tower Bridge project, it is quite possible that Khar'shan would have been nothing but an irradiated wasteland when the Reapers arrived less than ten years later. It is also possible that humanity would have been a mere husk of itself, or worse, at total war with the Citadel due to its genocidal response. Regardless of the what-ifs, the plan was totally inadequate to deal with an Alliance bypass of the Kite's Nest's fixed defences, and contributed heavily to the batarian's defeat.