Joseph Smith helps us to understand which wars this phrase refers to. In the 87th section of the D&C, he records that the time will come that war will be poured out upon all nations, beginning at this place (DC 87:2). This statement is made in the section in which he prophecies of the Civil War. If the Civil War is the beginning of the wars and rumors of wars, then certainly this phrase has reference to WWI, WWII, the Korean War, the Cold War, and many others. It probably also refers to wars which are yet to take place. Wars will continue until the Lord is done punishing the wicked, And thus, with the sword and by bloodshed the inhabitants of the earth shall mourn; and with famine, and plague, and earthquake, and the thunder of heaven, and the fierce and vivid lightning also, shall the inhabitants of the earth be made to feel the wrath, and indignation and chastening hand of an Almighty God, until the consumption decreed hath made a full end of all nations; That the cry of the saints, and of the blood of the saints, shall cease to come up into the ears of the Lord of Sabaoth, from the earth, to be avenged of their enemies (DC 87:6-7). This is the wrath of God spoken of in 1 Nephi 14:16.