As Klamath you could, yeah. Klamath doesn't have as much political power and leverage as, say, The Hub, so it'll be more at the mercy of the federal government than The Hub would be, but being one of the states in the northern frontiers would probably help it remain [i]somewhat[/i] semi-independent, and so it would probably have the ability to act on its own to some extent. Klamath would still be better off seeking approval from Shady Sands, maybe through its representatives (which you could control), though. So yeah, they could try for approval in expanding northward, but I imagine it'd have to carry the weight itself. This means fielding its own workers and guards, since the Republic is out-stretched and probably still hurting from the Mojave. You could try to get help from other states, though, who may or may not agree to help, for a price.