If you’re trying to guess whether people are Republicans or Democrats, knowing a few basic facts about them will take you a long way. What’s their race and gender? How far did they get in school? What part of the country do they live in and is their community urban, suburban or rural?

Between 2016 and 2020, for example, white Americans without college degrees favored the Republican Party by nearly 24 percentage points. Strike up a conversation about politics with such a person in rural central Maine, near where I live, and chances are that his or her sympathies will lie with the G.O.P.

Or consider gender and attitudes about crime and public safety: Men are about 10 percentage points more supportive than women of the death penalty and 10 percentage points less supportive of gun control. Or how about ethnicity and views on illegal immigration? Relative to Latino Americans, non-Latinos endorse “increasing deportation” as a partial solution by a 22-point margin.

Although there are certainly people whose politics defy generalization, the underlying demographic tendencies are powerful predictors of belief — powerful enough that elections have become as much a turnout game as an exercise in persuasion.

But this raises an important question. If our political views and behavior can be so easily predicted by characteristics like race (over which we have no control) or by factors like education (where our choices may be highly constrained by other things such as the social class of our parents), then when it comes to politics, are any of us really thinking for ourselves?

The accusation that people on the other side of the political divide have abandoned critical thinking and moral reasoning is now commonplace in American political discourse. Many on the left interpret the political tendencies of white voters without college educations as evidence that the Republican Party’s core constituency is ill informed or even unintelligent. Who else could fall for the lies of Donald Trump? Republicans, for their part, regularly invoke the idea of “liberal groupthink,” using it to make sense of how some of America’s ostensibly brightest minds could champion simplistic, unworkable policies like defunding the police.