The Times recently discovered that the Presidential candidate Ted Cruz failed to disclose a loan from Goldman Sachs that helped to fund his first Senate bid.

Senator Ted Cruz, of Texas, likes to portray himself as the straight-talking, shit-kicking, anti-establishment type. Last summer, when he was languishing in the G.O.P. primary polls, he went to the Heritage Foundation, in D.C., up the street from Union Station, and declared war on the “Washington cartel”—a cozy club of big banks, major corporations, and shadowy lobbyists that, he claimed, was quietly pulling the strings in the nation’s capital. “It operates like OPEC,” Cruz said, according to a report at Fortune.com. “I don’t know, like sheikhs, if they actually wear robes. But they nonetheless on a daily basis are conspiring against the American people.”

As Cruz’s insurgent campaign started making progress in the polls, he frequently zeroed in on the big Wall Street banks and the taxpayer-financed bailouts they received in 2008. During a televised debate that took place in November, he suggested that he would be willing to let a huge institution such as Bank of America go bankrupt, and he clashed with Ohio’s governor, John Kasich, a former managing director at Lehman Brothers, saying, “Why would you then bail out rich Wall Street banks and not Mom and Pop?”

To some political insiders, including his Republican enemies on Capitol Hill, Cruz’s bank bashing has always seemed somewhat opportunistic. Since he only got elected to the Senate in 2012, he didn’t have to vote on the 2008 TARP bailout, which many Republicans originally opposed; and, even after arriving in Washington, he didn’t express much concern about the details of bank regulation. And his actions in office have sometimes helped the industry: in 2014, for example, he famously tried to block a spending bill to protest President Obama’s executive orders on immigration—but, as Quartz’s Tim Fernholz points out, his political maneuvering may have distracted lawmakers from scrutinizing a rider, pushed by Wall Street lobbyists, that was attached to the spending bill. The rider reversed one of the new regulations introduced after the financial crisis, which had forced big banks to move some of their risky financial derivatives out of their federally insured divisions and into separately capitalized subsidiaries.

It was also well known in political circles that Cruz’s wife, Heidi, is an investment banker and a longtime employee of Goldman Sachs, a firm that has come to symbolize—fairly or unfairly—the power and influence of Wall Street. According to a March, 2015, article in USA Today, Heidi Cruz joined Goldman in 2005 and ran its Houston wealth-management unit, which, the report said, “handles portfolios for clients with an average net worth of $40 million.” Last spring, she took an unpaid leave of absence from Goldman to work on her husband’s campaign.

Cruz, evidently, didn’t see any contradiction between his family’s ties to Wall Street and the political positions he was taking on the stump. He even acknowledged, when asked about the company earlier this year, that Goldman is a member of the dastardly cartel that’s bilking the American people. “Like many other players on Wall Street and big business, they seek out and get special favors from government,” he said, according to an investigative story in the Times.

Going into tonight’s G.O.P. debate, in South Carolina, the Times story is the talk of the political class. The author, Mike McIntire, revealed that, in 2012, Cruz used a loan that his wife took out from Goldman to help to finance his successful Senate campaign, during which he honed his reputation as a critic of bank bailouts and corporate cronyism. The Goldman loan, which was for between two hundred and fifty thousand and half a million dollars, wasn’t disclosed to the Federal Election Commission, as it should have been. Rather than publicly acknowledging its existence, Cruz subsequently told reporters that he and his wife had liquidated practically all of their personal savings to help pay for the campaign.

Based on McIntire’s inspection of the annual ethics reports that Cruz and other Senators are obliged to file, which require them to list all of the assets they own, this appears to have been a fib. In addition to taking out the loan from Goldman in 2012, which was a margin loan attached to a brokerage account, the Cruzes took out a credit line, of similar size, from Citibank. Between the beginning and end of 2012, the value of the cash and securities that the family owned didn’t diminish to zero, or anything near it. Rather, it “saw a net increase of as much as $400,000,” McIntire reported.

The Cruz campaign sought to brush off the Times story. A spokeswoman told McIntire that the failure to report the loan from Goldman to the F.E.C. was “inadvertent.” Cruz himself told reporters, “if it was the case that they”—the two bank loans—“were not filed exactly as the F.E.C. requires, then we’ll amend the filing.”

From a legal perspective, Cruz probably doesn’t have much to worry about. Taking out personal loans to finance political campaigns is perfectly legal: candidates from both parties do it all the time. Disclosure violations can result in fines being levied on campaigns, but they aren’t exactly rare, either.

The issue for Cruz is a political one. Will the Goldman Sachs link prompt some Republican voters to question his authenticity? His entire persona is built on the notion that he is an outsider and a renegade. If he came to be perceived as just another member of the metropolitan political-financial élite, it could be very damaging to him.

The timing of the story was also bad for Cruz. Having staked his Presidential bid on winning in Iowa, he is facing a strong challenge from Donald Trump, who recently raised the “birther” issue. (Cruz was born in Canada to a mother who was an American citizen and a father who was, at that time, a Canadian citizen. Trump, ignoring the opinion of many lawyers, claims that this raises questions about whether Cruz is eligible to be President. Cruz gave up his Canadian citizenship in 2014.) Until last week, most of the Iowa polls showed Cruz ahead, but that has changed in recent days. Of the past five surveys that have been published, four of them have shown Trump leading—and the latest one, published on Thursday, has Trump up by six percentage points.

We will find out at tonight’s debate whether Trump and Cruz’s other Republican rivals seek to exploit the Times story. It seems quite likely that Kasich will go on the attack, and others may too, but it will be particularly interesting to watch Trump, whose non-aggression pact with Cruz is looking frayed. As a frequent beneficiary of bank loans himself, in his business dealings, and on a much larger scale than Cruz was, Trump isn’t objectively in much of a position to criticize. But that has rarely stopped him in the past.