Immigration restrictions close-off large portions of the earth to large proportions of the earth’s population. For those who regard the earth and its natural resources as belonging to mankind equally and in common, this is a morally impermissible state of affairs. This is because, if the earth and its resources belong to all equally, then the exclusion of anyone from any portion of the earth will be a violation of their natural ownership rights. A commitment to Natural Resource Egalitarianism (NRE) (...) is therefore held to entail a commitment to substantially more open, or even fully open borders. This paper does not seek to directly refute the claims of NRE, but rather seeks to demonstrate the failure of arguments from NRE, to establish the moral necessity of a general opening of borders. This paper addresses the two most prominent accounts of Open Borders NRE—Equal Division NRE and Egalitarian Ownership NRE—as well as a more recent attempt to advocate for open borders by combining these two positions into a so-called ‘Combined Model’. This paper argues that none of these three positions can plausibly and coherently account for the moral necessity of open borders. (shrink)