NEW YORK — The fire and fury over Michael Wolff’s book has largely centered on the personalities and power struggles within the White House. But behind all of that lies an important political development, one that explains the real rift between Donald Trump and his former chief strategist, Steve Bannon. President Trump seems to have abandoned populism.

Remember candidate Trump? His signature issue was immigration, on which he promised an unyielding hard line, including a border wall and mass deportations. His “Contract with the American Voter” was brimming with populist measures, from tough actions against China to a trillion-dollar public works program. His economic plans focused on goodies for the middle class, from a 35 percent tax cut for middle-class families to deductions for child and elderly care. He called for severe restrictions on lobbying and for term limits on members of Congress.

Trump’s final campaign ad featured images of billionaire financier George Soros, Federal Reserve Chairman Janet Yellen and Goldman Sachs’ CEO Lloyd Blankfein, darkly narrated by a Trump speech in which he warns against the “global power structure that is responsible for the economic decisions that have robbed our working class, stripped our country of its wealth and put that money into the pockets of a handful of large corporations and political entities.”

Flash forward to President Trump today. There is no wall, and the president now speaks of a “bill of love” that could offer a path to citizenship for the millions of undocumented immigrants he once promised to deport. His relations with China have been decidedly chummy, as have those with another country he excoriated on the campaign trail, Saudi Arabia. The main focus of his economic program has been to return vast sums of money to large corporations. Most of his tax law’s benefits go to those firms and to people in the highest income brackets.

Oh, and these economic policies are being designed and implemented by Blankfein’s former No. 2 at Goldman Sachs, Gary Cohn, and a former Goldman partner, Steven Mnuchin.

More so than the personality clashes between Bannon and Jared Kushner, and the gossip about who is up and down in the White House, this is the great divide that developed in the early months of the Trump administration. Bannon must have watched with incredulity as the candidate who campaigned as a fiery outsider against the Republican establishment essentially handed over the reins of his government to House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell. McConnell is quoted in Wolff’s book as saying, “This president will sign whatever is put in front of him.” Moments after Trump blasted Bannon last week, McConnell’s political team tweeted out a GIF of the majority leader beaming.

Where did Trump’s populism come from in the first place? To answer this question, the book to read is not Wolff’s gossipy confection but Joshua Green’s highly intelligent “Devil’s Bargain.” In it, Green points out that Trump had a mish-mash of political views that leaned in no particular direction. But he began going on talk radio and addressing conservative audiences and realized that it was not economics but social and cultural issues like immigration that got the crowds fired up. Trump was initially “indifferent to the idea” of a wall, according to Green, but campaign aide Sam Nunberg is quoted as saying that when Trump tried out the idea for the first time at the Iowa Freedom Summit in January 2015, “the place just went nuts.”

Unencumbered by any deep ideology of his own or any ethical qualms — as demonstrated by his embrace of birtherism, for example — Trump was able to adopt these issues far more quickly than his 16 competitors in the Republican primaries. He distinguished himself by taking on the most hard-line positions, and thus winning over the GOP base. That, in addition to his colorful, charismatic style, created a bond between him and a new bulwark of the Republican Party, the white working class, that appears, for now, unbreakable.

I don’t agree with many of Steve Bannon’s proposals, but he was surely right in recognizing the populist fury that runs through a large swath of the country. One wonders what will happen to it as time passes and Trump’s voters notice that they have ended up with something quite different than they had imagined. During the presidential transition, Bannon told Wolff that the Trump era would be like America in the 1930s, with a massive public works program that would get blue-collar workers back into shipyards, mills and mines. Instead we appear to have a return to the 1920s, an era of unrestrained capitalism, giddy market exuberance, a shrunken state and dramatically rising inequality. Is this what the laid-off steelworker in Ohio voted for?

Fareed Zakaria is a columnist with The Washington Post. His email address is: comments@fareedzakaria.com.

Fareed Zakaria