Evolution is the process by which things gradually change. Biological evolution occurs through natural selection.
In the political realm, evolution can occur due to capitalism's having a greater tendency to produce an increased civilian population as well as naval and other armed strength, and to enable even defeated countries to rebuild relatively quickly. As Ludwig von Mises notes, "The peoples who have developed the system of the market economy and cling to it are in every respect superior to all other peoples. The fact that they are eager to preserve peace is not a mark of their weakness and inability to wage war. They love peace because they know that armed conflicts are pernicious and disintegrate the social division of labor. But if war becomes unavoidable, they show their superior efficiency in military affairs too. They repel the barbarian aggressors whatever their numbers may be."
Thus, many governments that failed to practice capitalism have collapsed or been defeated by capitalistic nations and forced to become capitalistic. Notable examples would include Soviet Russia and Nazi Germany. They suffered brain drains to freer countries and were not able to keep pace with the industrial growth of the market economies.
Some theists believe that God guides the process of evolution along through repeated intervention. Ludwig von Mises writes, "Society is a product of human action, i.e., the human urge to remove uneasiness as far as possible. In order to explain its becoming and its evolution it is not necessary to have recourse to a doctrine, certainly offensive to a truly religious mind, according to which the original creation was so defective that reiterated superhuman intervention is needed to prevent its failure."
- Gordon, Thomas. "No. 63, Civil Liberty produces all Civil Blessings, and how; with the baneful Nature of Tyranny". Cato's Letters. https://en.wikisource.org/wiki/Cato%27s_Letter_No._63.
- Trenchard, John. "No. 64, Trade and Naval Power the Offspring of Civil Liberty only, and cannot subsist without it". Cato's Letters. https://en.wikisource.org/wiki/Cato%27s_Letter_No._64.
- Gordon, Thomas. "No. 65, Military Virtue produced and supported by Civil Liberty only". Cato’s Letters. https://en.wikisource.org/wiki/Cato%E2%80%99s_Letter_No._65.
- Mises, Ludwig von. "The Limitation of Offspring". Human Action. http://mises.org/humanaction/chap24sec2.asp.
- Mises, Ludwig von. "A Critique of the Holistic and Metaphysical View of Society". Human Action. http://mises.org/humanaction/chap8sec2.asp.