Nations can, and do, punish people for crimes they commit elsewhere on the planet. Nobody can get away with staking land out on the moon and declaring sovereign

Nations can, and do, punish people for crimes they commit elsewhere on the planet. Nobody can get away with staking land out on the moon and declaring sovereignty, because it's impossible to exist on the moon without a massive support apparatus on earth enabling it. It's easy enough to throw those people in a cell. And either nations take care of the offenders and form treaties, or it leads to war at the worst.