It was a combination of the carryover from my Goodreads rating (2 stars = "it's okay") and the fact that I thought they overstated greatly Agnew's significance. Everything else I've read about the Nixon administration suggests that he was a marginal figure and not the right-wing heart of things as they tried to make him out to be.
Oh, OK, I see. His enthusiasm for his subject and the notion that they thought (quoting from the podcast, from memory) "they were really onto something" -- particularly in light of the Tea Party and Trump's election -- certainly did come thrhough in the interview, and it actually did make me wonder whether you really can trace such a direct line back to Agnew. Tangentially perhaps, yes, and Buchanan might be one of the links in the chain (if any) ... but it sounded like most of the book was about Agnew himself, and they only tagged on the connection to more recent events at the end, without too much elaboration? (Also, it sounded a bit like the link with today was at least partly based on the notion that Agnew might have furthered these recent developments and so they might have happened a lot earlier if he hadn't been forced out of office and vanished into oblivion afterwards -- in other words, a sort of nonfiction alternative history thinking?)
That's a pretty accurate reading of their take. It presumes, of course, that Agnew 1) could have won the Republican presidential nomination in 1976 (very unlikely IMO, especially with Reagan waiting in the wings), 2) could have won the November election (questionable at best), and 3) would not have shed his attack-dog persona and governed more moderately much as Nixon had after 1976. I also tend to think of Agnew as less a harbinger and more another data point in an ongoing shift in the Republican Party that went back at least to Goldwater, if not Joe McCarthy. Here I could very well be wrong, but then if the authors are correct they didn't really make a good case for it.
I found it interesting listening to this interview back to back with the one on right wing radio in the 1950s -- which incidentally also would seem to contradict these authors' take on Agnew, in that the "attack dog" techniques of the early right-wing talk radio broadcasters also were similar to Agnew's, as was, at least in part, their (and Goldwater's and McCarthy's, and Buchanan's, and ... and ...) target audience. Isn't the real story here the shift in *both* major parties ... with the Republicans gradually picking up more and more of the election votes no longer going to the Democrats, particularly with the onset of the Civil Rights movement?