• Billionaire former New York City Mayor Mike Bloomberg's entrance into the Democratic primary has crystallized Sen. Bernie Sanders' central campaign theme.  
  • Bloomberg's self-funded campaign, which has already spent over half a billion dollars, has also reinvigorated Sen. Elizabeth Warren's bid, which has centered on her wealth tax. 
  • The Democratic debate in Las Vegas last week centered the class war on a national stage.
  • The two most progressive candidates' approaches to addressing income inequality are fundamentally different that that of their more moderate Democratic competitors. 
  • Visit Business Insider's homepage for more stories.

Billionaire former New York City Mayor Mike Bloomberg jumped into the Democratic presidential primary in November to give Sen. Bernie Sanders, now the national frontrunner, a run for his money. 

But Bloomberg's money-soaked ascent in the polls has crystallized Sanders' theme of "standing up to the billionaire class," a message that's made the primary a referendum on economic inequality and the perils of crony capitalism.  

In many ways, Bloomberg is the ideal foil for progressives. 

He's the eighth richest person in America with a net worth of over $65 billion and has already dropped over half a billion dollars of his personal funds on his campaign. Meanwhile, Sanders is running a grassroots-funded, populist bid to fundamentally restructure the US economy as fellow progressive Sen. Elizabeth Warren has made taxing the uber-rich a 2020 rallying cry. 

Regardless of whether Sanders prevails in the primary, the newest billionaire candidacy will only stoke the fire of economic populism. 

'A moral analysis' 

Class warfare was the theme of last week's Democratic debate in Nevada — the first that Bloomberg was eligible for.

Anand Giridharadas, a writer and high-profile critic of the ultra-rich, noted that the word "billionaire" came up more frequently during the Nevada debate "than 'China,' America's leading geopolitical competitor; 'immigration,' among its most contentious issues; and 'climate,' its gravest existential threat."

Sen. Elizabeth Warren kicked off the night by calling the former mayor and Wall Street executive just "another arrogant billionaire," much like President Trump. 

The moderates jumped in for their own swings at the newcomer. Former Mayor Pete Buttigieg insisted he would raise taxes on billionaires and noted he's the only candidate in the field who's not a millionaire or a billionaire. 

"I don't think you look at Donald Trump and say we need someone richer in the White House," Sen. Amy Klobuchar quipped.

But Sanders was the only candidate to frame his class-based argument in terms of right and wrong.

"Mike Bloomberg owns more wealth than the bottom 125 million Americans. That's wrong. That's immoral," he said. 

This is consistent with Sanders' messaging on the issue – he introduced his wealth tax proposal last fall by announcing "billionaires shouldn't exist."

FILE PHOTO: Former New York City Mayor Mike Bloomberg and Senator Bernie Sanders are seen on video screens in the media filing center during the ninth Democratic 2020 U.S. Presidential candidates debate at the Paris Theater in Las Vegas, Nevada, U.S., February 19, 2020. REUTERS/David Becker/File Photo
Former New York City Mayor Mike Bloomberg and Senator Bernie Sanders are seen on video screens in the media filing center during the ninth Democratic 2020 U.S. Presidential candidates debate at the Paris Theater in Las Vegas

It wasn't the first time a progressive with a massive platform has made that argument. 

Rep. Alexandria Ocasio-Cortez, Sanders' most prominent endorser, rattled the political establishment last year when she argued that it is "immoral" for billionaires to exist in a society with widespread poverty. She supports using taxes not only to fund expanded government services, but to redistribute wealth and trim "excess."

"At what level are we really just living in excess and what kind of society do we want to live in?" she asked. 

Warren, who built her political career fighting a system she says is "rigged" for the wealthy, hasn't gone so far as to support the abolition of billionaires. But the Massachusetts lawmaker has made her wealth tax the foundational proposal of her 2020 bid. 

And just this week, Warren appeared on the Late Show with Stephen Colbert to participate in a game of "How Well Do You Know the Billionaires That You're Gonna Take Away Their Money?"

The laughs came at the expense of Facebook CEO Mark Zuckerberg, who Colbert joked "looks like he cut his own bangs with toenail clippers," Amazon CEO Jeff Bezos, who looks "like the underbelly of a hairless cat," and Warren's two billionaire primary competitors, among other ultra-rich men.  

Giridharadas also focuses his attention on the billionaires, who he argues have rapidly expanded their influence over politics and American society, moving the country toward plutocracy. 

"I think the biggest thing that a lot of Americans don't realize is that we live in a functional oligarchy," Giridharadas told Insider last year. "I think that used to be a crazy thing to say, but I think more and more Americans just recognize that to be a factual description of reality … We are not who we think we are."

This is fundamentally distinct from the center-left approach. 

"This isn't an economic analysis, this is a moral analysis," Howard Gleckman, a senior fellow at the nonpartisan Tax Policy Center, told Insider. "For Sanders and Warren, a punitive tax, reducing the wealth of rich people, is a goal in itself."

While Buttigieg, Klobuchar, Biden, and even Bloomberg say they'd hike taxes on the wealthiest, they don't get anywhere near demonizing extreme wealth. 

Experts argue the economic populism of 2020 has its roots in the rapid growth of wealth inequality in the 1980s and 1990s and was triggered by the Great Recession. 

"This has been building up — in Brexit, in Trump, in Sanders in 2016 — and now it's a revolution," Michael Lind, co-founder of the left-leaning think tank New America, told Insider. He added that Democrats who support Bloomberg reject pitting the 99% against the 1% — or the 0.1%. 

Lind argues that the class war is now between the broader "managerial elite," made up of the college-educated and professional class on one side, and the working-class and non-college educated on the other. Bloomberg has attempted to weaponize that view of the class war by accusing Sanders of being "a millionaire with three houses," while Sanders and Warren focus on only the very wealthiest in society.

But much of the case progressives are making — to hike taxes on the very rich and get big money out of politics — is broadly popular among the electorate, and particularly so among Democratic voters. Polling has long shown that a majority of Americans believe the wealthiest and corporations don't pay enough in taxes.

Sanders' case for economic populism, Lind argues, is central to his appeal among the white blue collar voters who've made their way into the GOP's ranks in recent years. 

It remains to be seen whether Sanders, if he's the nominee, can significantly expand the Democratic party's appeal and reframe it as the party of the working class. But Bloomberg's bid has clarified that economic populism is the central issue of the 2020 primary.