In November 2016, my Facebook feed was filled with friends’ dreaded anticipation of Thanksgiving with extended family, and particularly with that uncle: the unapologetic Trump supporter full of crude, bigoted bluster. So many white families seemed to have an uncle like this — even if in liberal families everyone had written him off as a mean, eccentric old coot — that political pundits felt the need to weigh in on dinner etiquette.

At the time, I noticed the pattern, but I assumed that the similarities among uncles were organic, coming out of similar subject positions as older white men angry to see their privilege eroding. But after reading historian Brian Rosenwald’s Talk Radio’s America: How an Industry Took Over a Political Party That Took Over the United States, I suddenly understood those obnoxious uncles, and so much more about the past few years’ politics, in a new way. These men’s crude rants, their language of resentment, their belittling tone, their crazy conspiracy theories, their desire to “own the libs” – they modeled it on conservative talk radio hosts, and on television and internet personalities that emerged from talk radio. In some ways, they may be the isolated, angry old men their younger, more liberal relatives took them to be. But through decades of engagement with right-wing radio, they have coalesced into a community and voting coalition around a shared set of values, an agreed-upon litany of enemies, and a common rhetoric. And their avatar is Donald Trump.

As Rosenwald explains, talk radio did not set out to be the propaganda arm of the Republican party. In the 1980s, a.m. radio was rapidly losing ground because of f.m. radio’s higher-quality sound for music broadcasting, and it desperately needed a new business model. Talk show hosts, especially Rush Limbaugh, created a new and highly entertaining format that did not require high-quality sound, and they quickly drew a dedicated and profitable audience. Stations reaped the profits and broadcast more hours of conservative talk radio to rake in the earnings. And further, Rosenwald argues, conservative media did not, in fact, come to be at the beck and call of the Republican party. If anything, in that relationship, conservative media has come out on top.