This is an excellent request. You are completely correct. Many people in power have used art to further their claims and power. In fact, we see this all over the place. Let me give you a few examples.
First, the Romans were experts at doing this. For example, after the emperor Trajan defeated the Dacians, he put up a column that still exists today and on the column we see great art work to show the power of the Romans and their victory.
Second, we see something similar in the area of religion. Think of the great cathedral in the world. All of these are filled with great art work to show their power and glory. The very act of entering into a cathedral shows power. This is also true or Mosques.
Finally, people with money do the same thing. Art is a projection of something. For example, in front of Rockefeller center in New York, there is a huge statue of Atlas carrying the world. This is suggestive of the wealth and power of the Rockefellers and those with money.
You might want to study the work of Diego Rivera. The Revolutionary government in Mexico used him to promote their poltical views.