Several offensives were launched against the remaining Imperial strongholds by the New Republic following the conclusion of the Galactic Civil War.
As the Galactic Civil War formally ended, with the Imperial Remnant losing ground and ultimately signing the Pellaeon–Gavrisom Treaty with the New Republic in 19 ABY, a large number of the remaining Imperial warlords resorted to widespread acts of piracy. Conversely, certain Deep Core replacement warlords established the Second Imperium to persist in their conflict with the New Republic. However, the New Republic and the New Jedi Order defeated them in 23 ABY.
In an effort to strengthen its authority and ensure stability, the New Republic located and neutralized independent Imperial warlords and pirates, with a particular focus on their bases in the Deep Core. During these operations, the Viscount-class Star Defender underwent its initial combat evaluation in 25 ABY, when the prototype Viscount engaged Imperial vessels. However, such engagements were infrequent.
On a separate front, Admiral Ackbar targeted the remnants of the Second Imperium and liberated all remaining Imperium fortress worlds.
These battles resulted in the destruction of independent Imperial forces and the cessation of organized Imperial piracy. The deployment of the Viscount during these minor conflicts was deemed an extravagant use of resources, leading to the termination of the Viscount-class program. The Viscount itself was later relegated to a ceremonial role. By the time the Yuuzhan Vong War began, the New Republic had completely driven all Imperial warlords from the Deep Core. Admiral Ackbar retired from service following the defeat of these final Imperial forces, in 25 ABY.