Sarah Rice/Getty Images In last week's presidential debate, Democratic candidate Hillary Clinton said rival Bernie Sanders had smeared her by mentioning that she accepted money for giving speeches to Wall Street.

WASHINGTON -- Democrats are fuming over presidential hopeful Hillary Clinton's defense of the millions of dollars she made giving speeches to Wall Street. Her latest effort to push back against critics undermines years of Democratic claims about the influence of money in politics, invoking a central tenet of the Supreme Court's Citizens United decision.

In last week's head-to-head debate with Bernie Sanders, Clinton accused the Vermont senator of deploying a "very artful smear" against her by bringing up the $675,000 she received for speaking at Goldman Sachs.

"I really don't think these kinds of attacks by insinuation are worthy of you," Clinton said to Sanders. "If you got something to say, say it directly. But you will never find that I have ever changed a view or a vote because of any donation I've received."

The audience booed Clinton over the exchange. She also raised a lot of eyebrows beyond the debate hall.

"I can see how in the heat of hand-to-hand political combat, that might be an appealing defense," says Kurt Walters, a campaign manager with the anti-corruption group Rootstrikers, referring to Clinton's "smear" line. "But just like the Citizens United line of thinking, it ignores all of the other ways that money influences politics beyond the explicit exchange of cash for a vote."

Like Clinton, the Citizens United relies on a narrow definition of corruption as straightforward bribery -- a literal trade of money for votes. Previous Supreme Court decisions, like McConnell v. Federal Election Commission, had applied a broader standard than Citizens United -- one in which money can exercise an "undue influence" over policymaking, even absent explicit quid pro quo deals.

And while Democrats have long acknowledged that a check from a big donor might not result in a politician switching her position on an issue, they have argued that campaign contributions can buy a phone call or a meeting in which a donor can make his case -- opportunities unavailable to mere voters.

"The argument that contributions don't affect politicians' conduct is contrary to my experience," says former Rep. Brad Miller (D-N.C.).

Fundraisers give donors a chance to hobnob with candidates and discuss issues and ideas important to them. That has an impact on the way politicians see the world and how to solve its problems.

"Rich people have the opportunity to get access," millionaire Clinton donor Bernard Schwartz explained to Bloomberg's Max Abelson.

Clinton's paid speeches only compound the problem, since the money goes not to a campaign account or a super PAC, but to the candidate herself (Clinton has directed some speech revenue to charities, including the Clinton Foundation.) But like a fundraiser, the speeches also provide a well-heeled audience access to Clinton and a chance to ask her questions.

"Clinton, like our Supreme Court, ignores thousands of years of human experience in how money corrupts politics not just through quid pro quos, but also by shaping attitudes," says David Cay Johnston, a Pulitzer Prize-winning economics writer.

Clinton's statements during the debate contradict the goals of her very broad and robust campaign finance reform platform, which has been lauded by money in politics experts. She supports everything from public financing of elections to corporate disclosure of political spending to a constitutional amendment to overturn Citizen's United.

Voters, however, are accustomed to hearing politicians ignore campaign finance reform promises after entering office (both Presidents Bill Clinton and Barack Obama ran as reformers, only to embrace the status quo). Since Clinton rarely discusses her campaign finance reform platform in debates, her defense of her Wall Street speeches has largely overshadowed it.

And when Clinton served as a senator from New York, her relationship with Big Finance was always more complex than the simple portrait of a tough-talking reformer that she has painted on the campaign trail. Clinton has repeatedly touted a December 2007 speech she gave at NASDAQ that serves as an instructive example of the twists and turns in her oversight record.

"I went to Wall Street in December of 2007 before the big crash that we had, and I basically said, 'Cut it out!'" Clinton said in an October 2015 debate.

The actual speech was pretty easy on Wall Street. After repeatedly emphasizing that financiers only bore partial responsibility for problems in financial markets, she urged Wall Street players to reach a "voluntary solution" to the mess. If they couldn't, Clinton said, she would "consider" legislation. The tool she said she might eventually support -- lawsuit protection for mortgage servicers who modified loans -- wasn't particularly strong, since servicers were already required to offer troubled borrowers relief if doing so would prevent bigger losses from foreclosure.

By December of 2007, bank watchdogs in Congress had long since given up hope that Wall Street could fix things on its own. The subprime mortgage market had imploded 18 months earlier. It had been five months since two Bear Stearns hedge funds had collapsed. On Capitol Hill, Rep. Miller and Sen. Dick Durbin (D-Ill.) had already introduced foreclosure relief legislation that would have allowed bankruptcy judges to reduce the amount that borrowers owed on their mortgages -- just as they can for credit card balances and other debts.

Banks were fighting the proposal tooth and nail. If Clinton had wanted to be tough, she could have voiced support for her colleagues' legislation. She didn't.

Was this milquetoast approach due to a specific campaign donation? Almost certainly not. Did it have something to do with the fact that Clinton was a senator from New York? It seems plausible. Did Clinton sincerely believe she was doing what was best for the country? There is no evidence suggesting that she did not. Is it a "smear" to suggest that Clinton's relationships with Wall Street donors played a role? No.

Some Clinton surrogates aren't just reinforcing her Citizen's United-friendly argument -- they're hurling insults at people who are troubled by her close ties to Wall Street donors.

"If [Clinton] takes the money, she gets hit with this McCarthyism of the left, this guilt by association, even though there is no evidence that taking this money has had any impact on her policies," former Rep. Barney Frank (D-Mass.) told Politico last week.

Back when Clinton wasn't facing a tough primary challenge, Frank suggested that it was impossible for politicians to avoid being influenced by donors.

"People say, 'Oh, [the money] doesn't have any effect on me,'" Frank told NPR in 2012. "Well, if that were the case, we'd be the only human beings in the history of the world who, on a regular basis, took significant amounts of money from perfect strangers and made sure that it had no effect on our behavior."

Zach Carter is a co-host of the HuffPost Politics podcast "So, That Happened." Subscribe here or listen to the latest episode below:

﻿Also on HuffPost:

PHOTO GALLERY Hillary Clinton's Celebrity Donors