The Democratic primary finally got nasty in New Hampshire as Hillary Clinton and Bernie Sanders traded body blows over Wall Street and what it means to be "progressive."

The quiet deference that marked previous debates vanished Thursday night as Clinton came out firing against Sanders for insinuating that her campaign contributions from Wall Street would cause her to be soft on the industry. "If you've got something to say, say it," she said. "It's time to end the very artful smear that you and your campaign have been carrying out."

Clinton held her own in this exchange but she continues to struggle mightily when it comes to explaining the hundreds of thousands of dollars she received speaking to Goldman Sachs and other big banks.

"I did go on the speaking circuit," she said. "I spoke to heart doctors, I spoke to the American Camping Association, I spoke to auto dealers, and yes, I spoke to firms on Wall Street. They wanted me to talk about the world, what my experience had been as secretary of state."

This was an improvement over her response in a forum Wednesday night that she took the money because "that's what they offered." But she stumbled again when asked if she would release transcripts of her speeches to Goldman and others, saying only that she would "look into it."

It's hard to figure out how Clinton has not managed to come up with a better approach. The easiest thing of course would have been to think of the headache the Wall Street speeches would give her in a presidential campaign and just not have done them in the first place. Short of that she could have donated the money to charity months ago. She could still do that now. The Clintons are not hard up for cash.

On the transcript front, it's possible the contracts she signed would require that the companies Clinton spoke to also agree to release the text. If she asked, they almost certainly would. She should just do it and stop the bleeding.

These speeches tend to be high-level overviews though there could be passages in the remarks to banks over causes of the financial crisis that might make some on the left wince. There could also be the usual host flattery that typically marks these high-paid speeches. And that could be fodder for attack ads.

But if Clinton doesn't release the text she will continue to be dogged by attacks that she has something to hide. She already has problems with her use of private email and donations to the Clinton foundation. A display of total transparency would be a nice change of pace and possibly buy Clinton some good will.

Whatever she decides, Clinton is still not likely to lose the nomination to Sanders. The Vermont senator will likely win New Hampshire by a comfortable margin but when the race turns to Nevada, South Carolina and Southern states on Super Tuesday, Clinton will likely re-establish herself as the dominant front-runner while piling up delegates at a rapid clip.

The one thing that makes a quick Clinton win uncertain is money. Sanders is piling up millions in small donations and will have plenty of cash to go on the air in states more friendly to him and stay in the race, possibly for months.

This is where Clinton's Wall Street problems crop up again. The former secretary of state is much more reliant on large checks to fund her campaign, and many of those come from the financial industry. She has postponed two fundraisers with bankers in the last two weeks amid heavy criticism from Sanders for leaving Iowa last week to raise money at a financial firm in Philadelphia. But she needs the money and so will have to hold the events and then take hits from Sanders and the left once again.

Ultimately, unless new revelations emerge on the email front, Clinton will eventually be free of Sanders and be able to focus on the general election. The question is how beat up she will be by then and whether her campaign is broke in the weeks and months before the Democratic convention.

And if she winds up facing off against Sen. Marco Rubio — which is the most likely outcome — Clinton will probably yearn for the days where her toughest opponent was a self-professed socialist.

—Ben White is Politico's chief economic correspondent and a CNBC contributor. He also authors the daily tip sheet Politico Morning Money [politico.com/morningmoney]. Follow him on Twitter @morningmoneyben.

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