ooc:
One more suggestion (in case rebels do not want to actually war) is that rebels declare independence in a peaceful constitutional way and then comes Luthori troops and organizes huge massacre of independence supporters to keep control. That should look fine for public relations and maybe even Luthori allies see the true face of Luthori empire. On other hand Luthori gets control over the whole Beiteynu/Yishelem.
No need for terrorists and bloody conflicts, just agree to your people being IC slaughtered by empire. That could lead to rather huge RP stories when world just can not stand by watching innocent people killed for their dream of freedom.
"We killed those people because there was a Treaty!"