Fan Casting J'onn J'onzz in Justice League: Knightfall

Yet another Justice League member chooses to take the side of Superman, as the Martian Manhunter joins the insurgency against Batman's new regime, with him taking on the role of overseeing the far reaches of space outside of Earth, just in case any outside threat attacks both the rebellion and the regime. That way, the rebellion would know about it prematurely.