I thought this was a great book even if I disagree somewhat with JG's analysis of the Trump phenomenon. This book is a reasonable length, and it tells an important story about how the Democratic Party has changed in the last 50 years, with a focus on the last ten. Greene moves quickly but always provides adequate context and social science analysis, making for a brisk and interesting read.
I'm a kind of middle-of-the-road liberal Democrat (voted Clinton and Biden in 2016 and 2020 primaries) who often finds myself frustrated with the progressive wing of the party (especially the academic left). On the other hand, Liz Warren was my second choice by a hair in 2020, so I am on board with a lot of the progressive economic reforms and programs advocated by the 3 main characters of this book: Liz, Bernie, and AOC. Greene gives great biographies of all three to illustrate how they shifted the Democratic Party leftward on economics. Biden, for instance, was pretty much your classic neo-liberalish Clinton Democrat for decades, but he has governed to the left of Obama on most economic issues. That's a testament to the groundswell of pressure and new ideas created by these newcomers (or in some cases old-newcomers).
But it also reflects a broader historical story that Greene tells very well. Democrats since the New Deal had been the party of labor, the working class, black people, but also southern segregationists. This alliance started to collapse in the 1960s and eventually splintered completely in the face of the Reagan juggernaut. To keep up with Republican fund-raising prowess, Democrats like Tony Coehlo started to pull more support from Wall Street, which was often socially liberal but economically free-market. The tide of ideas at the time also tilted toward neo-liberal reforms and the removal of regulations, lowering of taxes on the wealthy, minimizing of welfare programs, etc, and Democrats hewed more to this line as well, a trend that peaked under Clinton. These moves were understandable in their time if a bit cynical, but they further cut the cords between the party and the white working class.
Little groundswells of discontent with neo-liberal popped up here and there but never gained much traction until the 2008 financial crisis. Not only did the perfidy and greed of Wall Street and the mortgage industry screw millions of Americans, Bush and Obama again chose to prioritize stabilizing big banks and industries like the car industry over helping ordinary people, who lost their homes and jobs and often could not relocate to where opportunities existed (in contrast to prevailing economic theory's predictions). So while left-populism was in part a response to the financial crisis, it was also a response to Obama's business-friendly governance, the slow recovery, and structural unfairness in the economic system as a whole. The rise of left-populism is really an attempt to weaken the Wall STreet-Democratic Party connection and rebuild links to the working class.
I do have a few small critiques of this book though. First, I think Greene underplays race/culture as explanations for Trumpism: fear of demographic change, cultural change, resentment at a changing country, nostalgia, and just straight up racial prejudice. Of course this is mixed with "economic anxiety," but Trump really only appeals to the white working class, so the usefulness of a class-centric explanation is limited. There's also a lot of granular voting data to show that Trump voters are actually way more white middle class than they might seem, and that they put issues like culture and immigration above bread and butter economic issues.
Second, Greene is aware of a big problem for progressivism but I think he still downplays it: it isn't that popular, and it is popular mainly among whiter, well-educated people. AOC's primary campaign, for example, won votes mainly from more educated white gentrifiers, not the mixed-race working class that many on the Left imagine they are connected with. Greene talks about the huge gap between an increasingly educated, urban, and economically stable (if not wealthy) strata of people who manage the Democratic Party and the larger working class of any race, which is often resentful of and alienated from the educated progressives' rhetoric and ideas. The Party, in short, may not want Wall Street, but it has also consistently rejected Bernie-style social democratic policies, showing that it is still pretty center-liberal (closer to Liz Warren's pro-regulated capitalism than Bernie or AOC's positions).
This book has important messages for progressives/the Left, a group I often sympathize with but do not fully identify with: you have to institutionalize yourselves and work within the system, including with people whose ideals and goals you don't share fully, to achieve much of anything. Ideological and moral purity is the enemy of getting anything done. And in the age of an insane GOP, compromises will have to be made, and you will have to rally around the Democratic candidate even if it is someone like Joe Biden. Overall, I think their presence has been a good thing for the Party: it ensures a wider range of ideas, more energy at the base, and challenges the neoliberal complacency that wasn't really working.
Greene's book is an excellent guide to all of this. I recommend pairing it with Michael Kazin's "What it Took to Win," which tells a deeper history but reaches similar conclusions.