Recent polls contain a surprising combination of results: Democrats appear to be leading in six tough Senate races even as President Joe Biden trails former President 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.

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.

Here are six themes that emerge from the six campaigns:

Populism

Successful campaigns, like movies and novels, tend to have both heroes and villains. Republicans are comfortable with this idea.

Their bad guys in recent years have included criminals, immigrants in the country without legal permission 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. All six senate candidates — in Arizona, Montana, Nevada, Ohio, Pennsylvania and Wisconsin — are basing their campaigns around a populism that harshly criticizes both big business and China.

The criticism of business focuses on the parts of corporate America that the candidates say have made life hard on working families.

“I’ll never stop fighting to crack down on corporate greed,” Sen. Sherrod Brown of Ohio says in one ad. Sen. Bob Casey of Pennsylvania talks about corporate “greedflation” and “shrinkflation.”

One Casey ad, set to “Pink Panther”-style music, shows fictional CEOs sneaking around a supermarket at night to shrink product sizes.

In an ad for Sen. Tammy Baldwin of Wisconsin, workers talk about how “Wall Street greed” slashed their pensions and say that Baldwin “fought like hell” to restore them.

A Brown ad includes a truck driver who says Wall Street tried to “screw Ohio workers.”

An ad for Sen. Jacky Rosen of Nevada boasts that she “took on the big drug companies — and won.” In an ad introducing Ruben Gallego, an Arizona member of Congress running for Senate, he says, “The rich and the powerful — they don’t need more advocates.”

Gallego adds, “It’s the people that are still trying to decide between groceries and utilities that need a fighter for them.”

The other villain is China, which the candidates portray as using unfair trade tactics to undermine American jobs.

The first television ad by the campaign of Sen. Jon Tester of Montana described China as “the greatest threat facing our nation.” Baldwin, in one of her ads, says, “We can’t let China steal Wisconsin jobs.”

In one Brown ad, workers at a washing-machine maker joke about his reputation for looking rumpled, disheveled and wrinkled — and say they don’t care because he fights to protect their jobs.

Brown’s blue-collar reputation is central to his uncommon electoral success in Ohio. He is the only Democrat to have won a Senate, governor or presidential race in the state over the past decade.

He, Tester and Sen. Joe Manchin of West Virginia (who’s retiring) are the only Democratic senators who represent states that Trump won in 2020.

This kind of populism, in which politicians promise to fight for ordinary people against the powerful, was once core to the Democratic Party. Franklin D. Roosevelt and Harry Truman were more populist than many people now remember.

Bill Clinton’s 1992 campaign was notably populist, too, as was Barack Obama’s 2012 reelection campaign.

It’s true that almost all elected Democrats today favor some populist policies, such as raising taxes on the rich.

But as the party has become dominated by college graduates, it has tended to emphasize issues that fail to resonate with working-class Americans. Remember, most Americans don’t have a bachelor’s degree.

Not the Campus Left

Climate change. Student debt. Diversity, equity and inclusion. The war in the Gaza Strip.

These topics are central to progressive politics today. They are the subject of campus protests and online debates. They are also almost completely absent from these six Democratic campaigns.

Why? The campaigns avoid the issues important to highly educated progressives but that matter little to most voters, especially working-class voters.

Student debt and housing costs make for a useful comparison. Student debt, a subject that the Biden administration has emphasized, may seem like the ultimate pocketbook issue.

In reality, it’s more niche: Only 18% of US adults have any federal student debt.

That helps explain why, in a recent Harvard University survey of US residents between 18 and 29 years old, student debt ranked dead last when pollsters asked respondents which of 16 issues mattered to them.

Israel and Palestine ranked 15th of 16. Climate change was 12th — and, again, this was a poll of Americans. younger than 30. The top three issues were inflation, health care and housing.

No wonder that student debt is largely missing from these Democratic campaigns, while housing — a cost almost every family faces — is a focus. Rosen has devoted an entire ad to housing costs in Nevada.

Tester’s campaign lists the “housing crisis” as one of Montana’s biggest problems.

A clarifying point about American politics is that people who follow it closely are very different from swing voters.

Bipartisanship

As polarized as the country is, many voters still hunger for bipartisanship. In their ads, the six Democrats generally treat Republicans with respect and celebrate collaboration.

Brown boasts about working with Republicans to pass a semiconductor law. Baldwin shows videos of Trump and Biden in one ad, and a narrator explains that she worked with both to crack down on Chinese imports.

Rosen brags of being “named one of the most bipartisan senators.”

The issue on which the Democrats try hardest to distance themselves from their own party is immigration, which polls show is a major Biden weakness. Rosen tells voters that she “stood up to my own party to support police officers and get more funding for border security.

A Tester ad says that he “fought to stop President Biden from letting migrants stay in America instead of remaining in Mexico.”

Abortion

This is the issue on which the Republican Party is out of step with public opinion, and Democrats are on the offensive.

Rosen describes her likely Nevada opponent, Sam Brown, as “another MAGA extremist trying to take away abortion rights.” Tester, when listing the ways he fights for Montanans, says, “We’ve got folks who want to take away women’s right to choose.”

That said, abortion remains a secondary issue in most of these campaigns.

Patriotism

“Growing up poor, the only thing I really had was the American dream,” Gallego says in the opening line of an ad. “It’s the one thing that we give every American no matter where they are born in life.”

That sentiment is typical of the six campaigns’ unabashed patriotism. Gallego highlights his Marine service in Iraq. Veterans’ health care is a theme of a few campaigns. An ad for Casey that is focused on Pennsylvania steel includes the line “Take that, China.”

Diversity, but Subtly

The candidates’ ads portray a diverse America. When Rosen talks about housing, she shows a racially mixed group of young couples. A Brown campaign ad about the Ohio steel industry stars both Black and white workers.

In a Baldwin ad, a Wisconsin businessman with a European accent praises the senator for fighting against federal rules about cheese making. Gallego talks about his mother’s struggles as an immigrant.

But the campaigns treat diversity as a natural part of American life, rather than as a political project. They emphasize the commonalities of Americans with different backgrounds. It’s a different approach from an identity politics that centers race.

Gallego has even achieved some notoriety for mocking the term Latinx. It disrespects the Spanish language, he has said, and is “largely used to satisfy white liberals.” He barred his congressional office from using the term.

It reminds me of a point that Steve Bannon, the far-right political strategist, has made: When American politics focuses on race, Republicans — such as Mr. Bannon and Trump — tend to benefit.

The flip side is that when campaigns focus on economic class, Democrats have the chance to benefit. You can see that lesson in these six populist campaigns.