How hereditary are political leanings in the United States?

Question

I have scrolled through political Twitter. One person said something along the lines of "my parents are swing voters but I am a solid vote blue all the way through Democrat".

The general public is close to evenly divided, while younger individuals clearly lean left in both ideology and partisanship. This begs the question how much is politics passed down in the United States?

For example, if voters under 30 are voting for Joe Biden by 25% and Hillary Clinton by 20% and the rest of the public is statistically tied, it shows that there are age based differences, which leads to my question.

The question: how often is a political viewpoint passed down in the United States?

Answer 1

The research on this is pretty muddy, but the answer would seem to be "Some, but not very."

Historically, researchers observed a strong correlation between parent political identity and child political identity - including political identities of "unengaged" and the like. More recent research has observed that a lot of the studies that measured that concordance assumed that the political identity began first with the parent and was passed to the child.

As early as 1968, Jennings and Niemi called out these flaws and suggested alternatives to measuring the directionality of political identity transmission. So while a large congruence was observable, there seemed to be a whole mess of factors that contributed to it, not just simple parent->child transmission.

The factors that contribute to successful parent->child transmission, however, are a little better understood. Jennings, Stoker, and Bowers (2009) did a three-generation study and found that the strength of the political identity, and how active the parents were in politics, contributes greatly to that political identity being acquired by the children.

However, more recent research by Ojeda and Hatemi (2015) finds things like child->parent transmission which - despite the durability of the direct parent->child transmission model, is easily discovered to occur. Any model of the transmissibility of political identity and parent/child relations needs to account for this, and so they open a line of inquiry which they revisited in 2020.

Their model basically says that children will acquire their parents' political identity more frequently not only when that ID is strongly held and regularly performed, but also when the parent->child relationship is supportive and nuturing.

Interestingly, the strength of education seems to induce a sort of rebellion effect where the child will actively reject what they believe their parents' political identity to be. (The child's understanding of their parents' political identity is not necessarily good.)

tl;dr - There is some correlation between parental political identity and that of their children, but the forces that contribute to it are many and strong - parental political ID, even where there is great congruence, is probably not the dominant force causing that congruence, except in healthy, closely held family ties.

Answer 2

Not just in the United States, but a peer-reviewed scientific study says people are somewhat predisposed to different political beliefs based on their genes. The study is called Genetic Influences on Political Ideologies: Twin Analyses of 19 Measures of Political Ideologies from Five Democracies and Genome-Wide Findings from Three Populations published in 2014 & while the environment plays a factor, your genetics (or nature) does play a decent sized part in someone's political leanings. A 2011 study says the same thing about genetic factors which was called Left or right? Sources of political orientation: the roles of genetic factors, cultural transmission, assortative mating, and personality.