The Cartel made great efforts to attack the Federation systems. They used a whole fleet of powerful ships led by the flagship dreadnought for their raids.
During the invasion, the Aliens attacked the Cartel flagship — it was seriously damaged, yet still retained combat capability.
The Cartel is repairing the dreadnought using all its resources to continue the attack.
Since all the Federation fleet forces have been sent to defend the systems from the invasion, it is vital to prevent the Cartel from restoring the dreadnought and using it to continue attacks on our positions.