The aim of the present paper is to carry out a comparative study of Immanuel Kant and Jürgen Habermas on democratic governance and citizenship. Both thinkers focus on these two factors but the extent to which these contribute to reinforcing the state and peace has not been investigated by researchers. The present paper questions how cosmopolitanism in comparative and consequential mode: Safeguards peace by presupposing a level of interstate institutional convergence as presented by Kant and Habermas; and Reinforces and innovates democracy on an interstate level not only within the state; and Instead of just safeguarding peace, re-discovers the political sphere, as presented by Habermas, who on this point develops an array of departures from Kant. The originality of the research derives from the symmetries and asymmetries in Kant and Habermas that extend their arguments on cosmopolitanism to the solidification of democracy and the avoidance of war.