well tough question... i say we take off and nuke the entire planet from orbit... its the only way to be sure
But which faction would send in that nuke? That would depend on the outcome, if it was a Space Marine Fleet then Magneus would win, if it was a Chaos Fleet, Abaddon would win, if it was an Eldar Craftworld, then Eldrad would win, and if it was an Ork fleet, then Gazghkull would win.