Recent polls contain a surprising combination of results: Democrats appear to be leading in six tough Senate races even as President Biden trails Donald Trump in the same states.

What are these Democratic Senate candidates doing right? To answer that question, I studied their campaigns, looking at advertisements, social media posts and local news coverage. In today’s newsletter, I’ll highlight the single biggest theme that emerged: The six Democrats are basing their campaigns around a populism that harshly criticizes both big business and China.

(In a follow-up newsletter, I’ll look at several other campaign themes.)

It’s still early in the campaign, obviously, and some candidates who are leading now may lose in November. Still, most of the Democrats in these races aren’t merely ahead in the polls; they also have a track record of winning tough races by appealing to voters who are skeptical of the Democratic Party. I think that their use of populism is crucial to that appeal.

Successful campaigns, like movies and novels, tend to have heroes and bad guys. Republicans are comfortable with this idea. Their bad guys in recent years have included criminals, illegal immigrants and cultural elites. Democrats are sometimes squeamish about naming antagonists (other than Republicans) and prefer a higher-minded version of politics.

This year’s swing-state Democrats are not squeamish. They portray both China and big business as making life hard on working families. Here’s a flavor of what they are saying about corporations:

  • Senator Bob Casey of Pennsylvania talks about corporate “greedflation” and “shrinkflation.” One ad, set to “Pink Panther”-style music, shows fictional C.E.O.s sneaking around a supermarket at night to shrink product sizes.

  • In an ad for Senator Tammy Baldwin of Wisconsin, workers talk about how “Wall Street greed” slashed their pensions and say that Baldwin “fought like hell” to restore them. Brown has run a similar ad, in which a truck driver talks about how Wall Street is trying to “screw Ohio workers.”

  • An ad for Senator Jacky Rosen of Nevada boasts that she “took on the big drug companies — and won.” Senator Jon Tester of Montana and Ruben Gallego, an Arizona congressman running for Senate, also criticize Big Pharma.

  • “The rich and the powerful — they don’t need more advocates,” Gallego says in an ad introducing himself to voters. “It’s the people that are still trying to decide between groceries and utilities that needs a fighter for them.”