This depends on what the war was on. In general whoever loses the war is forced to obey the victor, but there are special cases. For example, if the victor invaded the loser in order to gain access to their resources, in my opinion the loser should be able to keep their sovereignty but should pay tribute to the victor in the form of the resources they wanted in the first place. However, if the victor was invaded and successfully fended the loser off, they should be able to demand retribution for the sacrifices they made during the war.