Complex sentence: Since "Earthkind" has grown from pack to village, to tribe, to territory, and then to nation, LTC Channon envisions going from nation to planet next, and thereby declares the First Earth Battalion's primary allegiance to the planet.
Split into simpler sentences: Since "Earthkind" has grown from pack to village to tribe to territory and then to nation, LTC Channon envisions next going from nation to planet. He thereby declares the First Earth Battalion's primary allegiance to the planet.