Pete Buttigieg’s recent disclosure of his former consulting clients intensifies a growing battle between Democratic presidential candidates over their ties to the private sector, worrying some in the party that an escalating series of purity tests could turn off voters and convey an exaggerated disdain for business.

The Democratic Party has long included a vigorous anti-corporate strain, but now the debate has turned more personal. The candidates’ back-and-forth about their professional and financial ties has put several on the defensive about everything from former legal clients to junior consulting work to donations from company executives.

“It’s imposing a purity test that you can never win,” said Rufus Gifford, a longtime Democratic activist and fundraiser who has donated to Buttigieg and former vice president Joe Biden, among others. “I just think we have to be very careful about the way we talk about it.”

Buttigieg, the mayor of South Bend, Ind., on Tuesday night revealed his client list from a 2.5-year stretch at McKinsey & Co. shortly after college. That followed weeks of demands from critics, notably Sen. Elizabeth Warren (D-Mass.), for greater transparency.

Buttigieg, for his part, has been targeting Warren’s corporate legal work when she was a bankruptcy law professor, successfully pressuring her to release information about her fees.

Democrats like Rep. Don Beyer (D-Va.), a Buttigieg backer who is traveling to Iowa soon to knock on doors, discounted the tit-for-tat. “I will be surprised if a single person says ‘I can’t be for Pete because he worked for McKinsey’ or ‘I can’t be with Elizabeth because she represented a client in a bankruptcy case,’ ” Beyer said.

The exchanges come amid an energetic embrace of liberal economic populism by the leading Democratic candidates. Warren is campaigning heavily on creating a new tax on the richest Americans and has made corruption a central theme; Sen. Bernie Sanders (I-Vt.), an avowed democratic socialist, routinely rails against the wealthy and decries “oligarchy” in the United States; Buttigieg and Biden warn frequently of the dangers of income inequality.

Many Democrats think such messages will be well-received by voters concerned about a widening gap between rich and poor. But they also fret that an increasingly aggressive tone could ultimately hurt the party, potentially creating litmus tests and exposing candidates to Republican accusations of a war on prosperity.

“A lot of the argument is ‘You’re going to get free college, free health care, a bigger bonus for retirement, and we’re going to give you a guaranteed income,’ ” said former Chicago mayor Rahm Emanuel, ticking through some of the candidates’ signature platforms. “None of it is about how we’re going to grow the economy and grow success.”

Emanuel served in the White House under Presidents Barack Obama and Bill Clinton, and the current turmoil reflects in part how much the political landscape has changed. Democrats under Clinton were at pains to prove their openness to corporate America; today, they are scrambling to show their distrust of it.

Several Democratic candidates have said they will reject donations not just from companies but also from corporate executives, arguing about whose refusal is strongest.

Sen. Cory Booker (D-N.J.), for example, announced he would reject contributions from pharmaceutical executives after he’d been criticized for being too close to the drug industry. “You can’t campaign wrong and then govern right,” he said at a CNN town hall in March, adding, “I will not take corporate PAC money, and I will not take federal lobbyists’ money.”

Biden also found himself caught by the transformed landscape. He initially opposed the creation of a super PAC to support his candidacy because it might conflict with his image as a middle-class champion. But when his campaign struggled financially, he abandoned that stance, allowing the formation of a pro-Biden super PAC.

That, in turn, prompted a harsh attack from the Sanders campaign, which declared that “super PACs exist for one reason and one reason only: to help billionaires and corporations bankroll a presidential campaign with unlimited amounts of money.”

But the recent crossfire between Buttigieg and Warren over their long-ago professional work has been especially pointed. Warren had avoided attacking her rivals by name, but in recent weeks she suggested that Buttigieg needed to disclose his clients from his days as a consultant for McKinsey.

Warren, who does not hold fundraisers with wealthy donors, also said Buttigieg should allow reporters into his own fundraising events. Buttigieg was being targeted by protesters labeling him “Wall Street Pete,” though the bulk of his career has been in the military and city government.

The client list Buttigieg released Tuesday night included Blue Cross Blue Shield of Michigan, the Canadian supermarket chain Loblaws and Best Buy, plus several nonprofit and government entities.

Many Democrats were unhappy to see the Warren-Buttigieg spat, thinking it could damage both candidates and harm the party. “A chicken can kill a chicken and eat a chicken,” said Chris Adcock, chairwoman of the Page County Democratic Party in rural Iowa. “They’re starting to henpeck each other. We’re eating our own.”

The irony, Adcock said, is that President Trump is viewed as one of the most corrupt and least transparent presidents in history. The candidates’ rush to satisfy Democratic primary voters could backfire, she said, as it forces candidates to release everything from client lists to legal payments to tax returns to medical records, even as Trump refused to do so.

“We know he’s not going to be transparent, so why did we have to do this to each other?” Adcock said.

Many liberal Democrats, however, see the new scrutiny as a long-overdue course correction by a party that had become too close to corporations and Wall Street, depriving it of an effective message.

“The more that our presidential candidates are putting these issues front and center, the more likely it is that a Democrat will win the White House,” said Rebecca Katz, a liberal strategist who has donated to Warren and others. The problem with “official Washington,” Katz said, is that “they don’t understand the struggles that so many people are dealing with every day.”

Even some of the more traditional candidates, like former Massachusetts governor Deval Patrick, said they recognize voters’ desire for new guardrails on corporate activity.

“Capitalism has earned its disdain,” said Patrick, who entered the race after leaving his job as a managing director at Bain Capital, a firm vilified by Democrats in the 2012 election. “We have practiced a kind of capitalism in this country in the last 30 or 40 years that was very short-term focused, without regard for the importance of the long-term consequences on the enterprise or on people or on the planet.”

Among the Democrats most concerned about the primary’s recent tone are House members who captured seats from Republicans in 2018 in upscale suburban battleground districts. Some said voters are not voicing the same complaints about corporations and the wealthy back home.

Asked whether he was hearing about such issues from his constituents, Rep. Tom Malinowski (D-N.J.), who has endorsed Booker, said, “No,” adding, “I’m not focused on that.”

When Rep. Mikie Sherrill (D-N.J.), who also won her seat in 2018 and supports Booker, was asked whether her constituents are pressing her to take on the wealthy, she responded, “I haven’t been hearing that.”

Pressed on whether Democrats should emphasize such ideas or run on the kitchen table issues she and her colleagues campaigned on last year, Sherrill praised bills to lower prescription drug prices and authorize defense spending.

If any candidate has set the tone for the party’s current rhetoric, it’s Sanders. The senator from Vermont often brings up “the billionaire class,” voicing anger at large companies he says have avoided paying their fair share in taxes. As former New York mayor Mike Bloomberg moved closer to entering the race, Sanders singled him out sharply at an Iowa rally, declaring, “Tonight we say to Mike Bloomberg and other billionaires: Sorry, you ain’t gonna buy this election.”

On Tuesday, Sanders unveiled a TV ad in Iowa with similar themes. “Huge tax breaks for the rich while the middle class continues to struggle,” he says in the commercial, while an image of Trump flashes on screen. “That’s what happens when billionaires are able to control the political system.”

His campaign said it welcomed the discomfort some in the party are expressing. “Corporate greed has run the country for too long and working people are sick and tired of it. If pointing that out makes the political establishment uncomfortable, that’s a good thing,” Sanders spokesman Mike Casca said in a statement.

There is little doubt the candidates are responding to a newly populist mood in both parties, and Democrats across the political spectrum say they are comfortable with calls to raise taxes on the very rich. Still, many say, the party needs to do a better job of outlining an economic agenda that can break through at a moment when the labor market is strong.

Some worry they are giving Trump ammunition to paint all Democrats as socialists. “You can be hostile to income inequality, you can be hostile to concentration of wealth and those kind of things,” said Rep. Tim Ryan (D-Ohio), who dropped out of the presidential race in October and supports Biden. “But you can’t be hostile to business, to free enterprise.”

One potential pitfall for Democrats is that if purity tests are stringent enough, it will be hard for any candidate to survive unscathed.

Biden, who has cultivated a “Middle Class Joe” image, has enjoyed an explosion of wealth from book deals and speaking fees in recent years. Sanders achieved millionaire status by writing a best-selling book.

“There’s way too much focus on what somebody else has,” said former senator Heidi Heitkamp (D-N.D.), reflecting on the candidates targeting the wealthy, “and not enough on how you’re going to right the economy.”