Immanuel Kant, in his political project, "Perpetual Peace" has attempted to show a moral hope for the scourge of humanity, i.e. war. For Kant, man's intrinsic selfish nature is a cause of constant collision that can be controlled by universal laws of reason to ensure an enduring peace among the warring nations. But is this idealistic approach towards war equally applicable to concrete particular situations of humankind? What if there are conditions under which war becomes inevitable or even a desirable alternative? Can the choice of war be a morally justified alternative? And again, with the choice of war, can we ever hope for perpetual peace? It seems not! There are certain conditions when humanity is put at stake and war turns out to be the ultimate way to find peace Kant hinted but has not explored at length. In this paper, I want to explore and expound on these human conditions by bringing the situational examples of Mahabharata and its idea of Dharma Yudha (righteous war). Mahabharata serves as illuminating justifications for irremediable difficulties and dilemmas behind the inescapability of war in certain human circumstances. I will try to understand how far this "realistic" effort is ethically warranted in the way of seeking peace. I argue that although the Kantian universal model of rejection of war is a valuable ideal, and Mahabharata's realistic solution in terms of recognition of righteous war is relevant on the practical ground, both these positions of morality and corporality do not seem to provide a sufficient means of achieving perpetual peace in a contingent world, and therefore, it requires to look at some other alternatives. In doing so, an attempt will be made to critically analyse the incessant struggle between universal and particular, or idealism and realism by highlighting the existential contingencies and ambiguities of human finitude in the light of Kant and Mahabharata in relation with perpetual peace and war.