 Kant holds out the third model as the ideal form for the correct international institution. He calls the world republic an “idea” (8:357), a term that Kant uses for concepts created by the faculty of reason that cannot be met in experience but that can serve as models or goals for actual human behavior (the social contract is another idea of reason in political philosophy). The ideal international union is a federation of states that has coercive power over member states but whose decisions arise from debate and discussion among those member states. Kant is unclear regarding whether that coercive force is to be realized by joint action of member states, sanctioned by the federation, against a non-compliant member or by a distinct international force controlled by the federation itself. The precise status of states’ membership is also not clearly stated: he generally says that states have a right to withdraw from the federation, although he often states that the federation is indissoluble and even indicates in the “Doctrine of Right” that states may go to war to “establish a condition more closely approaching a rightful condition” (6:344), implying that states can be coerced into membership. Kant recognizes that actual states will balk at this international federation since rulers will object to such a surrender of their sovereign power. Kant thus argues that the second model, a league of states in which each state opts to negotiate with other nations instead of waging war, must be adopted as a “negative surrogate” (8:357). In a league of states, individual nations are allowed to leave at will and the league itself has no coercive powers over members. States voluntarily agree to settle disputes in a way that avoids war and encourages further peaceful relations. Leagues of states need not extend worldwide but should expand over time in order to approximate a worldwide union of all states.