Metaphysical idealism underpinned much of the political philosophy of the classical, medieval and early modern periods. Its strength was that, in holding that values such as justice, natural law and reason are implicit in the structure of reality itself, it gave thinkers a firm and universalist perspective from which to judge existing arrangements and engage in political advocacy. However, the emergence of empirical and scientific approaches to political theorising. Political idealism has been criticised on the grounds that it encourages political energies to be expended on goal that may be unrealistic or unachievable that it fails to recognise the extent to which political actions is determined by practical considerations such as the pursuit of power or the satisfaction of material interests and that, anyway, political ideals may be contested and lack universal authority. For example , realist theorists in international politics have long ridiculed the idealist's faith in collective security and international harmony. Nevertheless as example such as Mahatma Gandhi and Martin Luther King demonstrate, idealism has an undoubted and enduring capacit to inspire commitment