WASHINGTON — Hillary Clinton's presidential campaign on Thursday accused Democratic rival Bernie Sanders of breaking a self-imposed pledge against negative advertising, offering up the latest sign that her campaign is concerned about the Vermont senator's rise in Iowa.
The Clinton campaign cried foul after the Sanders campaign released a television ad in Iowa and New Hampshire in which he tells viewers there are "two Democratic visions for regulating Wall Street."
Sanders says one vision says it's "okay to take millions from big banks and then tell them what to do" while his plan would break up the big banks, close tax loopholes and make Wall Street pay its "fair share."
The ad does not mention Clinton by name nor does it delve into her family's acceptance of millions of dollars in speaking fees from Wall Street banks or financial contributions for her campaigns.
Sanders campaign manager Jeff Weaver said in an interview that the ad is not an attack. "Secretary Clinton is not mentioned anywhere in there. This ad is an indictment of the Wall Street wing of the Democratic Party," he said.
But Clinton's campaign said Sanders, who has said he has never run a negative ad during his political career, had broken his commitment not to engage in negative campaigning. "We were particularly surprised today to see him break that pledge and run this negative ad," said Clinton campaign manager Robby Mook.
Sanders' ad hit the airwaves as a new poll sponsored by the Des Moines Register and Bloomberg Politics showed a tightening race in Iowa, with Clinton at 42 percent and Sanders at 40 percent.
The Democratic race has increased in intensity.
After largely ignoring Sanders at campaign events, Clinton has more directly critiqued his record at the start of 2016, questioning Sanders' past votes on gun control and how middle-class taxpayers might be affected by his plan to create a single-payer Medicare for all health care system.
Sanders has vowed to break up large Wall Street banks that were bailed out during the financial downturn in late 2008 and 2009 and suggested that Clinton would be more lenient in how she would address the financial industry.
Sanders has said that the polls and Clinton's tactics show that she is nervous about her standing in the campaign. The two leading Democrats and former Maryland Gov. Martin O'Malley, who is running in a distant third place in polls ahead of the primaries, are set to appear for their final debate before the Feb. 1 Iowa contest on Sunday night in Charleston, S.C.
The former secretary of state has been the dominant front-runner for the campaign but has watched her advantage in Iowa diminish and trails Sanders in New Hampshire, his New England neighbor.
Clinton campaign senior strategist Joel Benenson said the Sanders ad marked a "new phase" in the campaign but would not commit to responding in turn with a similar ad. The campaign noted that Sanders pulled a digital ad in December that the senator felt fell into a "gray area" of negative campaigning.
"It's going to be up to him and we'll wait and see what he does," Benenson said. "He asked them to pull down the last one they put up, he might ask them to take this one down tomorrow."
O'Malley's campaign team sought to distance itself from the back and forth between Clinton and Sanders. Campaign manager Dave Hamrick said it was clear that "both Sen. Sanders and Secretary Clinton are wed to the failed, broken politics and tactics of the past."