Dark Empire states that "within days of Thrawn's downfall, surviving members of the Emperor's Ruling Circle, in concert with six former Starfleet commanders," formed a coalition and attacked the New Republic-held Core Worlds, such that The Essential Chronology states that "within days" this coalition had "conquered several key systems" (among these the Dark Empire Sourcebook lists "the nearby Kaikielius and Metellos systems"), culminating in an assault on Coruscant itself in "Retreat from Coruscant." Coruscant was declared an open planet and the New Republic relocated its seat of government to Da Soocha V, in the Cyax system.
The Dark Empire Sourcebook mentions the Imperial siege of Caprioril, a New Republic sector capital, and Coruscant and the Core Worlds describes the Imperial capture of Esseles III, Ralltiir, Duro II, and Corulag. Shortly after the events of Dark Empire, the Dark Empire Sourcebook states that the Empire had "regained the Core Worlds, and still holds the Deep Galactic Core, as well as many high industry regions beyond the Core Worlds," and resupplied from "power bases in the Mid-Rim and the reclaimed Inner Rim, where industrial planets depend on wartime economies to survive"; the campaign resulted in "linking Imperial holdings all the way to Wild Space."
By the time of Dark Empire II, the Essential Chronology states that the Empire had "consolidated the forces remaining in the newly subjugated Core and Colonies regions"; it adds that by Empire's End the Empire had "regained key territories in the Inner and Outer Rim." By this time, the Empire was the dominant power in the Deep Core, the Core Worlds, the Colonies, and the Inner Rim, with significant holdings in the Mid-Rim, Outer Rim, and Wild Space. The New Republic retained some territories throughout, and may have retained dominance in the Expansion Region.
Military Readiness
The New Republic Defense Force had suffered a number of strategic defeats during the campaigns of Operation Shadow Hand, and several more during the preceding fighting in Thrawn's War. The Jedi Academy Sourcebook indicates that as a result of the Imperial attack on Coruscant, the New Republic had "lost over 60 percent of the Army's command staff," including "the upper hierarchy" and "many of [their] best COs, even those stationed on other worlds." Nevertheless, shortly after the events of Dark Empire, the New Republic Intelligence Operations Command noted in a Top Secret memorandum to the Provisional Council that "militarily, we [the New Republic] still hold the winning hand and mostly likely they [the Imperials] realize this." Despite their territorial inferiority, the more-or-less intact NRDF concentrated on attacking key infrastucture, with Empire's End saying that they directed "troopships and heavy armor" against "Imperial supply ports and shipyards," including dispatching "a hundred thousand ground troops and their assault armor to the galactic rim" on board a single landing ship to join other forces in investing "a great Imperial shipyard under siege."
In contrast to the New Republic's dispersal, the Empire had adopted a policy of large-scale fortification. The Dark Empire Sourcebook states that in the wake of the Imperial coalition campaign that seized the Core, the Imperials "began bulwarking them against further attack" once "control of these vital planets was secured," and goes on to describe the rise of the so-called Fortress Worlds, with "perimeter defense squadrons" forming "an overpowering border guard," in addition to moons that "bristled with turbolaser and ion cannon emplacements" and asteroid belts "mined with anti-matter particles and reflecting satellite arrays for surface based beams." In addition to the Fortress Worlds, the Empire's main base of operations is the Deep Core, which the Dark Empire Sourcebook states includes "secret military facilities, shipyards, and training grounds for [the Emperor's] exclusive troops," and the Galactic Emperor had long since begun to "bring supplies and troops into the Deep Core" in preparation for renewed offensives. The Deep Core preserve was protected by the Imperial Hyperspace Security Net, combining interdictor technology with "connected non-mass transceivers linked by a network of coordinated hyperspace S-threads," allowing the Net to detect unauthorized hyperspace travel and force the ships into real space. The Net monitored all navigable routes in the Deep Core, and many of the routes were "mined, patrolled, and otherwise blockaded to prevent further unauthorized exploration."
Specific Conditions
The Dark Empire Sourcebook describes the Shadow Hand Strategy as being the Galactic Emperor's detailed plan for fighting the war (Operation Shadow Hand is the actual implementation of the SHS), so comprehensive the sourcebook calls it "an autopilot system for the Empire itself"; Palpatine considered it "a summation of [his] battle philosophy" that was "more important than any admiral or weapons system" and "made use of all his resources -- not simply COMPNOR or the military, but everything," including "his Dark Side Adepts and Dark Jedi." Even his closest advisors had access only "to as much of the plan as necessary," and "it was in their best interests to follow it precisely."
For the purposes of this scenario, consider the following to be an accurate description of the specific details of the SHS:
The SHS does not have any ability to use the Force, but does have extensive records on its capabilities, and can assign Imperial Force-users tasks to complete in pursuit of its objectives (which is absolute victory for Palpatine first and foremost, and also for the Empire whenever that is compatible with the first objective).The Shadow Hand Strategy is a comprehensive database of the Galactic Emperor's contingency plans, war plans, long-term political plans, and social-engineering programs. Assembled from years of hypothetical scenarios constructed by Palpatine as mental exercises and war gaming solutions, it contains decades' worth of planning and strategy. Variables are entered into the system, which then produces precisely detailed coherent instructions by assembling planning modules from the various existing entries into a single plan for dealing with all of the known variables. In this way, the Strategy can be adjusted to account for unforeseen circumstances while retaining continuity of planning, essentially providing an autopilot system for the Empire in Palpatine's absence.
In order to ensure the compatibility of the SHS's directions with his own plans, Palpatine stored the database within a supercomputer whose operating system is imprinted with his own personality. In essence, Shadow Hand thinks like Palpatine, and tailors its responses in the same way he himself would do. It makes all its decisions on the principal of what is best for Palpatine, and consequently acts with his full confidence. Its instructions are to be obeyed as though they were Palpatine's own, because in some sense they are.
Scenario
As seen in Empire's End, Palpatine of Naboo has met his final death on Onderon and Byss has been destroyed. However, Shadow Hand has survived intact, and adjusts its strategy to account for the loss of the Empire's headquarters and main stockpile of weapons of mass destruction. For the purposes of this scenario, the Imperial leadership continues to defer to Shadow Hand and carries out its instructions, forestalling any repeat of the post-Endor collapse and scramble for power (but may continue to harbor their own ambitions; as with Palpatine himself, their loyalty is conditional and not proof against betrayal). The war continues between the unified Empire, which controls the most territory in the galaxy, and the New Republic, which controls only disparate, widely-dispersed rump territories but retains the military upper hand.
Is it possible for the Shadow Hand-led Empire to win the war without the Galactic Emperor's WMDs? How long will the Imperial ruling class suffer to live under the dead hand of the Emperor? Can a computer with the knowledge and cunning of Palpatine maintain control of the Empire without his ability to use the Force? In the event that it wins the war and secures control of the galaxy, what can Shadow Hand do as a substitute for the apotheosis of Palpatine?