Well, in all reality, whoever wins at this point, it's still a win overall. Since Kaine DID support Thrawn (admiteddly only minor support) during Thrawns campaign to defeat the rebels.
According to the Essential guide to Warfare Kaine was going to fully back Thrawn and commit all his forces to his cause towards the end of Thrawn's campaign, then Thrawn died at Bilbringi which the NR then captured, Mt. tantiss was destroyed, Garos IV(and it's hibridium for cloak shields) was lost to an uprising and C'baoth was killed so all the advantages Thrawn had assembled were negated in hours. On top of this Thrawn's battle plans were known only to himself and therefore also lost. Under the circumstances I can somewhat understand Kaine's desire to return to fortifying the Alignment as he was certain it would soon be a target, rather than continue the offensive blindly.