Something new is happening in a New York Democratic primary contest: An incumbent is getting hit for being too close to Wall Street.

The unlucky congressman is Rep. Charles Rangel, who was called out by challenger Adriano Espaillat during a recent debate for a vote to water down Wall Street reform. Espaillat, a state senator, has been hammering Rangel for weeks over his ties to the financial industry. On Thursday night, Rangel pulled out of the final debate before the election.

Rangel, 84, has been in office since 1971, but is in a dead-heat with Espaillat in the primary for New York's 13th Congressional District, which represents Harlem and some sections of the Bronx. Rangel, Espaillat and a third contender, the Rev. Michael Walrond Jr., squared off in a debate Wednesday evening.

Espaillat attacked Rangel's 1999 vote to repeal the Glass-Steagall separation between traditional banking and risky securities trading, saying economists widely cited it as a cause of the 2008 banking collapse. Espaillat then asked why Rangel voted to roll back a key aspect of the 2010 Dodd-Frank financial reform law, referring to Rangel's support for a measure that would reinstate taxpayer support for risky derivative trades by big banks. The bill, HR 992, had been the subject of intense lobbying from the nation's largest financial institutions.

"Do you know who Barney Frank is?" Rangel responded sarcastically. "Barney Frank supported these changes in that provision of the law. Not only did he, but Nancy Pelosi and most all Democrats supported it."

Democrats, in fact, broadly opposed the bill when it passed the House in October 2013, with 119 Democrats voting against it and 70 voting for it. Pelosi was among the 11 Democrats who didn't vote.

When it comes to Frank's support, Rangel is being a bit cute. It's true that in 2012, Frank waived a similar bill through the House Financial Services Committee, but he has since said he did so because he knew the Senate would kill it. When HR 992 came to the House floor last fall, Frank came out of retirement to oppose it, issuing a joint press release with Rep. Maxine Waters (D-Calif.), who succeeded him as the highest-ranking Democrat on the House banking panel.

"It would be a mistake and destabilizing to repeal this provision," Frank said in October 2013. "I would vote against H.R. 992."

Espaillat has repeatedly reminded voters and the media that the bill Rangel supported was written by lobbyists for Citigroup, a top donor to Rangel.

Democrats in Congress traditionally have been able to cast pro-Wall Street votes without facing political repercussions at home. If Rangel is knocked out of office in the June 24 primary amid a flurry of attacks over derivatives legislation, it will likely change the calculation Democrats make on financial reform votes.