Indeed , but only after one side has forced the other into an untenable position and so altered the deal they can get . Look , really , give me this city now . I have destroyed your army and you can ' t defend it so if you refuse I will take it by force and we both know you cannot stop me nowOkay , okay . In return I demand the institutionalization of my religion ! No , but I would settle for nonpersecution of your followers at this point if you give me the city and promise never to challenge me . Alright , it ' s not the deal I wanted but it ' s the best one I can reasonably attain now . That ' s what war does . Unless , of course , it becomes a clusterfuck like Syria or a stalemate like Korea , where no side can gain a definitive upper hand and so force peace . All sides think they have a chance of winning still , and know that if they back down their ideology will be completely destroyed and probably put into a worse position than before the war .