Imperialism. It is a fatal flaw of civilization mixing with the desires of the human mind, resistance to imperialism has plagued civilizations all over the world since the dawn of its existence. Mars was humanity's first grasp into the void of space, establishing it as a rich colony for the extraction of raw materials for Earth.
Luna was established to make the transport of these materials between Earth and space easier, and this continued for quite some time. For over two centuries, both worlds functioned on co-dependence. Earth needed resources to build its industry while it fixed its rapidly declining ecosystems, and Mars needed to eat. Luna flourished from the resources passing through and became a hub of trade. This was the case until Mars began to build its own agricultural domes, beginning a push for self-sustenance. Able to feed itself and heavily taxed by the United Nations, now the sovereign government of Earth, Mars began to push for independence and tensions have been on the rise...