Let's logically examine the major power shifts of last 100 years:
Republicans, rewarding profiteering, bring on the Great Depression.
FDR leads nation during a world war and brings on a new era of hope for workers with The New Deal, thus setting the table for creation of The American Dream. FDR politics forces Republicans to politically move leftward, as evidenced by the GOP's 1956 platform:
https://twitter.com/politvidchannel/status/1072535944035753984
- politvidchannel
JFK makes a bid to recapture the spirit of FDR's New Deal but fails when assassinated.
LBJ fulfills promise on civil rights and voting rights, but develops the cruel War on Vietnam which defeats his presidency.
Nixon cracks down on civil rights, expands the war while ushering in new authoritarianism via the drug war and a clampdown on civil liberties and political protest.
Reagan-Bush move nation to right wing extremism using tactics of pro-war, union-busting, deregulatory and privatization policies, expansion of the drug war and manipulating the media with family values morality propaganda.
Democrats copycat Republican right wing policies and begin favoring corporate politics over people politics which pretty much brings us to where we are today. Much like the GOP moved left after FDR, the DEMs moved right after Reagan.