Approximately thirty years BV, Celzi population pressure coupled with the Dominion's official policy of escalating the cost of expansion based on how many planets a faction already owns reached a tipping point where the Celzi species were badly in need of new territory but couldn't afford to buy it. Their solution, after eight years of increasingly frustrated negotiation, was to secretly forge an alliance with the Qinis, Jeghiren and Lathk, who were also frustrated with Dominion policy, and declare secession from the Dominion, simultaneously annexing several unclaimed systems.
The Dominion did not accept this secession, and declared war in order to reclaim the unexploited systems, but between the explosive rate at which Celzi and Lathk reproduce, coupled with Qinis automated engineering and the well-developed Jeghiren shipyards, the Alliance was quickly able to build up its military to match the Dominion's.
The war soon bogged down into a bloody stalemate, and finally reached an uneasy equilibrium around about 5y BV. A formal ceasefire has yet to be declared, but both sides are now avoiding further violence, both eager to avoid any action which might persuade the human race to declare for the other side: both the Alliance and the Dominion recognize that deathworlder troops and military expertise would give that side an insurmountable strategic advantage.
--Copied from r/HFY/wiki/jenkinsverse