Each party had a diversity between liberal and conservative views depending on various issues. Things started to change when civil rights were enacted. For many this was a clarifying event and each party handled the change differently becoming a key voter concern. In 1944 only 5% of eligible blacks were registered and had little influence on national elections.
Democrats needed the support of southern Democrats. To get their support Franklin Roosevelt had to overlook anti-lynching legislation in order to implement the New Deal. A few decades later Barry Goldwater ran as Republican for president, advocating state's rights winning most of the former Confederate states being part of a sorting process.
Political identity has united many other identities. Racial attitudes could easily align with gun rights, tax reductions, LGBTQ rights, etc. It has reached the point where surveys have shown that increasing number of parents would be most upset if their child chose to marry someone of the opposite political persuasion.
Being intelligent too often takes a back seat to political reasoning. After a social experiment the author concluded "People weren't reasoning to get the right answer, they were reasoning to get the answer they wanted to be right."
Trump was seen by many Republicans who did not like him, as their best bet to get elected and get the judges and tax reductions they wanted.
Prior to 1970 party nominations were settled by party officials. Primaries opened up to members, but those most fanatical had a greater influence.
"It is easy to be in the middle of a muddle it's not easy to be in the middle of a chasm" This leads to fewer persuadables. A more effective strategy than trying to motivate swing voters is to activate your base to get them out to vote and demonstrate their support.
Most democracies have adopted a Parliamentary system that binds the legislative and executive systems, meaning that if one party loses an election another party will take over both systems. In contrast the United States has a Presidential system in which it is possible and fairly common for each party to have a share of the power and impede the efforts of the other party. This provides opportunities for the minority party to block legislation. "Bi-partisan cooperation is often necessary for governance, but irrational for the minority party to offer."
When newspapers dominated political coverage, most tried to avoid antagonizing either party to maximize their profits, although some papers took sides. When television and social media overtook newspapers, to maximize their profits some tried to be the most appealing to one side or the other., example Fox News.
The media decides what is newsworthy. For example Hilary's emails were given more attention than her policies. In 2016 Trump was given more media coverage than all of his 15 primary competitors combined. Obviously his ability to corral media coverage was among Trump's greatest skill.
Emotions matter more than reasoning and apparently our emotions are most stirred by how we feel about the other side. Media very often flames our feelings.
How do we improve the situation? Klein makes a few suggestions.
Instead of gerrymandering at state level a proportional representative system would represent the voters more fairly (and encourage more voting, more discussion and give third parties a fairer chance). It is too common for one party to win the popular vote, but end up with fewer representatives. This distorts the will of the people.
In 2040 it is projected that 70% of Americans will live in the 15 largest states meaning that that 70% of Americans will be represented by 30 Senators while 30% of Americans will be represented by 70 Senators. The electoral college already distorts who gets fair representation.
Votes should be as easy as possible. Restricting voters lessens credibility.
Washington DC and Puerto Rico should be states. Blocked for political reasons as too many blacks and Hispanics frighten otherwise fair minded Republicans. Author feels would increase Republicans veering from racist strategies as they would have to compete for their votes.
The author is more introspective than most political commentators. "We will never know how fully we have been shaped by our contexts" We all need to be more mindful that we are influenced by more than one of our identities.
Klein, back in 2019 pointed out that the debt ceiling was unnecessary. As we now know it has become a very difficult partisan issue.
Most voters are focused on national politics, but in reality we have more influence on a local scale. The author suggests a focus on our local level would eventually influence national concerns. In the U.S. there are 537 elected federal officials, but in the entire nation (state and municipal), there are 500,000 elected officials. Many of the local officials will go on to campaign for federal offices.
The book covers the naturalness of polarizing in more depth and it is well worth reading.