On one level, the fight over O’Rourke is a fight over the legacy of Obama. The Obama veterans championing O’Rourke compare his “inspiration, aspiration, and authenticity” (in the words of Obama’s former campaign manager Jim Messina) to the 44th president’s. In a recent essay titled “The Case for Beto O’Rourke,” the former Obama aide Dan Pfeiffer declared that “the whole conversation around Beto has been eerily familiar to me, because these are the exact arguments people made to me when I told them I was considering working for Barack Obama 10 years ago.”

O’Rourke’s critics turn the analogy on its head. “Beto is a lot like Obama, true,” Bruenig acknowledges, but “it’s perhaps time for left-leaning Democrats to realize that may not be a good thing.” A recent Jacobin article called O’Rourke “Obama redux: an attractive, progressive-sounding, comforting figure” before declaring that Obama redux “would be disastrous,” given the former president’s policies on immigration, Wall Street, and war.

Read: Beto O’Rourke’s huge Facebook bet

But the argument is about more than Obama. The people criticizing O’Rourke for taking fossil-fuel money don’t want to just prevent the Democratic Party from modeling its next presidential candidate on its last president. They want to overturn a model that has long dominated the party. Since the mid-20th century, Democrats have generally treated corporations as legitimate participants in the political process. Today, for the first time since the dawn of the Cold War, a powerful faction within the party wants to treat them as ideological adversaries instead.

Progressive Democrats don’t talk a lot about William Jennings Bryan these days. But in important ways, he embodies the attitude toward corporations to which they’d like to return. In 1896, when the Democrats first nominated him for president, Bryan denounced “millionaires, who steal banks, mills, and railways,” “defaulters, who live in palaces and make away with millions,” and “money kings, who buy up Congress.” Bryan called American politics “a struggle between the idle holders of idle capital” and “the struggling masses, who produce the wealth and pay the taxes of the country.” Many corporations responded by sending their employees—along with their paychecks—“suggestions” that they vote for the Republican, William McKinley.

In Party Ideologies in America, 1828–1996, the University of Texas political scientist John Gerring argues that after Bryan’s loss “the accusation of illicit interference in the democratic process—via corporate contributions or employer coercion—would become a hallmark of Democratic campaigns” through the early-20th century. The party nominated Bryan for president twice more, in 1900 and 1908. And Gerring argues that Bryan’s antagonism toward corporations set a tone for Democratic leaders that continued—to varying degrees—through the 1940s. Woodrow Wilson, in 1912, warned that “the masters of the United States are the combined capitalists and manufacturers of the United States.” Franklin D. Roosevelt, in his 1936 inaugural address, boasted that “we have earned the hatred of entrenched greed,” and promised to battle the “political puppets of an economic autocracy.” Harry Truman, in 1948, savaged the “gluttons of privilege” from “Big Business” who “want a return of the Wall Street economic dictatorship.”