There are no permanent enemies between nations, nor permanent friends, only eternal interests. Similarly, when armies engage in battle, Luo Zheng can choose to collaborate with his arch-enemy Jackson for the sake of national interests. In the face of a common enemy, Luo Zheng doesn't mind working with Jackson. As for eliminating the enemy, and continuing to fight each other after the mission is completed, that's a matter for the future and not to be considered now. Everything is focused on the bigger picture.
