Are we here in the United States more polarized now then we were in the 1960’s?
— @Dermot Griffin
Probably not — Gnomon
I think we are much more polarized.
There was some polarization in the 1960s. Vietnam was the principle locus. Also hair length, hippie clothing and lifestyles, "bra burning" (in quotes because very few if any bras were burned) and such cultural issues. On the other hand, congress was much more collaborative; The two "bad guys", Presidents Lyndon Johnson and Richard Nixon, were not miles apart on many issues. Nixon, for instance, favored treatment as the primary response to drug use. The Watergate scandal did not separate conservatives and liberals -- in congress or the streets. Most people ended up being thoroughly appalled by the Watergate scandal.
Our present state of polarization has been building for quite a long time--way before Donald Trump slithered into office. I'd say it's been building since the last 40 years, ever since Reagan (1980-1988).
One of the theories about polarization says that the leading cause of civil conflict is the rise of marginalized groups, relative to the dominant group. One author put it this way: "white people mind getting poorer less than they mind black people getting richer".
The various minority growth that may tip demographics from white majority to white plurality in 20 years or so, has been accompanied by improvements in income among minorities in many places (certainly not everywhere). Better income, more education, more achievement, etc. It's not a zero sum game. Mexicans going to college doesn't reduce the number of whites in college, and improvement in minority income are not coming out of white people's wages. What is upsetting is the change in
relative status.
Racially, the two political parties in the US have become quite different. The Republican Party is mostly white and the Democratic Party is far more open to minorities (latinos, gays, blacks, asians, women, immigrants, etc.).
Economically, the US is mostly working class. The relatively-poor working class and the absolutely-poor working class are sharply divided economically from the 8% to 10% of the population who are either financially comfortable "middle class" or "very wealthy ruling class".
Mass media is a key part of our polarization. Elementary, high school, and even colleges are often less effective in teaching people how to live and think than in the past. Old mass media has largely faded--the three networks, the daily newspapers, and the like. The wild, unregulated internet has taken the place of more "civilized" and centrally controlled institutions.
The Atlanta Constitution, Chicago Tribune, or San Francisco Chronicle were never going to report that a gang of pedophiles was running the US Government. There is nothing to stop QAnon from claiming that there are pedophile orgies on the floor of the senate, or that Hillary Clinton is a reptilian alien.
Conspiracy theories are more compelling than nuts and bolts civics, economics, or public health. So JUST SAY NO! to vaccinations, masks, social distancing, and so on.