This study on "Wealth, Income and Power" by University of Santa Cruz sociology professor William Domhoff contains much of the data that I was looking for regarding how wealth distribution has changed historically in the US. It has a political viewpoint, because in another study Professor Domhoff says UC Santa Cruz is "the most liberal public university in the country." My kind of place! He even uses the word "liberal," although in other places he uses the less lovely "progressive." I prefer a "liberal arts" education to a "progressive" education. Anyway....
The shift in wealth and income in America is not as great as I had thought, but it's significant. I like graphs, so here's one from the study:
It shows the current distribution of wealth between the top 1% and the lower 99% as about the same as 1920. It got worse in 1930, probably as a result of the Depression, and then went up considerably to 1950, probably as a result of recovery from the Depression and World War II. One effect of both factors was that the government virtually took control of the economy during that period -- first to help prevent poor people from starving and going homeless, and later to devote all productive resources to the war effort. Then there was a big surge in the 1960s and 70s, probably as a result of the government's war on poverty and civil rights efforts. The distribution started getting worse again in the 1980s when Reagan was elected. Reagan changed government policies and tax rates to favor the rich.
Government policies are very important. Both Republicans and Democrats understand this. Republicans like the general slope of the curve since Reagan began favoring the rich. They plan to fight to keep it moving in a direction that favors the rich. I don't think this is good for America. It makes America different from the country that I grew up in during the 1960s and 70s. I still believe that part of the goodness of America during that period was that all members of the "Greatest Generation," rich and poor, had fought together in World War II, which had imposed some self-restraint on the greed of the leaders of the country, a restraint that does not exist today. Significantly, Reagan, although he served in the military during WW II, did not fight; he just continued to make movies in California, albeit for the military while in uniform. George H.W. Bush was a much better representative of the Greatest Generation than Reagan was.
The fight over where we go from here may lead to a government shutdown. But from the looks of this graph, the last shutdown did not have much effect.