John Wittneben simmered as he listened to Hillary Rodham Clinton defend her ties to Wall Street during last weekend’s Democratic debate. He lost 40 percent of his savings in individual retirement accounts during the Great Recession, while Clinton has received millions of dollars from the kinds of executives he believes should be in jail.

"People knew what they were doing back then, because of greed, and it caused me harm," said Wittneben, the Democratic chairman in Emmet County, Iowa. "We were raised a certain way here. Fairness is a big deal."

The next day, he endorsed Sen. Bernie Sanders in the presidential race.

Clinton’s windfalls from Wall Street banks and other financial services firms — $3 million in paid speeches and $17 million in campaign contributions over the years — have become a major vulnerability in states with early nomination contests. Some party officials who remain undecided in the 2016 presidential race see her as overly cozy with big banks and other special interests. At a time when liberals are ascendant in the party, many Democrats believe her merely having "represented Wall Street as a senator from New York," as Clinton reminded viewers in an October debate, is bad enough.

It is an image problem that she cannot seem to shake.

Though she criticizes the U.S. economy as being "rigged" for the rich, Clinton has lost some support recently from party members who think she would go easy on Wall Street excess if elected. Even as she promises greater regulation of hedge funds and private equity firms, liberals deride her for refusing to support reinstatement of the Glass-Steagall Act, a law that separated commercial and investment banks until its repeal under President Bill Clinton. (Sanders favors its restoration.) And for many Democrats, her strong support from wealthy donors and a big-money "super PAC" undercuts her increasingly progressive rhetoric on free trade and other economic issues.

Her advisers say most Democrats like her economic policies and believe she would fight for middle-class and low-income Americans. Most opinion polls put Clinton well ahead of Sanders nationally and in Iowa, and they are running even in New Hampshire, but she fares worse than him on questions about taking on Wall Street and special interests. And even if Clinton sews up the nomination quickly, subdued enthusiasm among the party’s liberal base could complicate efforts to energize Democratic turnout for the general election.

In the primaries, Clinton’s advisers privately concede that she will lose some votes over her Wall Street connections. They declined to share specific findings from internal polls, but predicted the issue could resonate in Democratic contests in Iowa, Nevada, Ohio and Michigan, where many people have lost homes and businesses to bank foreclosures.

Sanders zeros in on Wall Street donations to Clinton in an aggressive new television commercial that started running in Iowa and New Hampshire on Saturday: "The truth is, you can’t change a corrupt system by taking its money," he warns.

One of Clinton’s most prominent supporters in Ohio, former state Sen. Nina Turner, defected to Sanders this month in part, she said, because she felt he would be tougher on special interests. And some Democratic superdelegates, whose backing is crucial, said Clinton’s ties to big banks, and her invocation of 9/11 to defend her ties to Wall Street at the Nov. 14 debate, only made them further question her independence from the financial industry.

"My parents had a saying in Spanish — ‘Dime con quien andas y te dire quien eres’ — which means, ‘Tell me who you’re hanging with and I’ll tell you who you are,’" said Alma R. Gonzalez, an uncommitted superdelegate from Florida. "A lot of my Democratic friends feel that way about Hillary and Wall Street.

"Are the working people in this country going to be able to count on hard decisions being made by President Hillary Clinton with regard to her Wall Street chums?" Gonzalez continued. "Will she be another President Clinton who appoints a Treasury secretary from Wall Street? These are major concerns."

!~neIP~!Indeed, Bill Clinton’s close relationships with Wall Street executives like Robert E. Rubin of Goldman Sachs, whom he named his Treasury secretary, and his support for undoing parts of Glass-Steagall have contributed to misgivings about Hillary Clinton.

She has proposed imposing risk fees on unwieldy big banks and empowering regulators to break them up if necessary — though this is not the wholesale breakup that Sanders favors under a return of Glass-Steagall. She also proposes to make sure fines for corporate wrongdoing hit executive bonuses, and to pursue criminal prosecutions when justified.

Yet even though she has taken tough stands in the past, such as chastising banks for widespread foreclosures in 2007 and 2008, some Democrats are skeptical that she would ever crack down hard on the executives in her social circles in Manhattan, the Hamptons and Washington.

Jake Quinn, an uncommitted Democratic superdelegate from North Carolina, said he was concerned about Clinton’s willingness to clamp down on Wall Street malfeasance. "The financial sector’s ongoing relative lack of accountability makes me suspicious of any candidate who sources it for significant support," he said.

Clinton’s advisers say that she has advanced the strongest regulatory proposals of any candidate, putting the lie to claims that she would protect Wall Street’s interests as president. Any political harm resulting from her Wall Street ties would be minimal, they maintain, because she never took action in exchange for donations. They also play down the possibility that Clinton would face voter turnout and enthusiasm problems if she won the nomination.

While Sanders and another candidate for the Democratic nomination, former Gov. Martin O’Malley of Maryland, have argued that big donors inevitably had influence with her, her campaign has pushed back against suggestions that the financial services industry had bankrolled her campaign. Her aides also said ads by a new group, Future 45, attacking Clinton would only underscore her independence, because the group’s major donors include Wall Street magnates like Paul Singer.

"When billionaire hedge fund managers are forming super PACs to run ads attacking her, it’s clear they fear she will take action as president to crack down on the industry’s abuses," said Brian Fallon, a Clinton campaign spokesman.

Bashing Wall Street is not an automatic win for Sanders, however. Gonzalez, the Florida superdelegate, and some other undecided Democrats said they viewed Sanders as too hostile to banks and corporations and too divisive in his remarks about American wealth.

But others said they were more concerned that Clinton had not broken with Wall Street in a clear way, noting the lengths she went to at the debate to explain the relationship.

"She was waving the bloody shirt of 9/11 to defend herself, which we’re accustomed to seeing with demagogues on the right, and it just didn’t feel quite right," said Kurt Meyer, a co-chairman of the Mitchell County Democrats in Iowa, who has not endorsed a candidate. "She connected two things, 9/11 and her ties to Wall Street, that I didn’t like her sewing together."

Turner, the former Ohio lawmaker, said the blocks of foreclosed homes in Cleveland were a painful reminder that banks prioritize their own corporate interests. Sanders has been criticizing "the corrupt economy symbolized by Wall Street greed" for decades, she said.

"He shows righteous indignation and speaks for the common woman and man in saying they have a right to be outraged at Wall Street," Turner said. "He doesn’t just talk the talk. He walks the talk."

And Clinton? "Her ties are her ties," Turner said.