User blog comment:GrandMethuselah67/Character Sheet 19: Ramses, the Great/@comment-4867780-20150725034018/@comment-4867780-20150725052115

Yeah, this one. The Warp's denizens have a lot of trouble entering the material universe and sustaining their existence there. Their energies wear off pretty quickly without a powerful source, forcing them to return to their home dimension.

I'm pretty sure a full-on war against Kazzack would learn the Republic massively devastated, so even with the superior technology gained in the meantime, it would take a lot of time and efforts to recover from the losses and war effort, without even talking about facing a new and vastly greater threat.