Psalm 72 embodies the ideal that the Davidic dynasty wished to be seen by its subjects to fulfil. Rhetorical analysis shows that the conception of the king as the protector of the poor is offered as the sole justification for the world-wide dominion claimed for him. But this ideology, which presents the king as caring for the poor of his own people but claiming tribute from foreign nations, contains a moral contradiction, as well as concealing the truth that the king was supported by domestic exploitation. However, the appropriateness of the model of the tributary mode of production is questioned in the light of the evidence for private property rights. The ideology draws its plausibility from an ancient tradition of royal measures in favour of the poor. Although direct evidence is limited, it will have been to the advantage of the judaean dynasty to take such measures in order to repress the independent power of local elites. The text suppresses this interest of the king, as well as his own exploitative activity, in favour of his alleged concern for the poor, and thus harmonizes the interests of the king with theirs. But it achieves this at the expense of the doctrine of unconditional divine election, deriving the king's legitimacy from his fulfilment of the divine will in his 'option for the poor'. The psalm's permanent ethical value lies in that it treats state authority as legitimate only if exercised on behalf of the weakest members of society.