It was the first promise Bernie Sanders made as a presidential candidate.

“I’ve never run a negative ad in my life,” Sanders told reporters at the Capitol exactly nine months ago, at the brief press conference he held to declare his candidacy. “I hate and detest these ugly, 30-second negative ads.”

As Iowa voters prepare to caucus on Monday, the Clinton campaign is accusing its surprisingly strong rival of repeatedly breaking that pledge. “Sanders Campaign Doubles Down on Last-Minute Barrage of Negative Attacks,” read the subject of one Clinton campaign email Thursday. A day earlier came a similar email: “Facing Pressure, Sanders Turns to More Negative Attacks, Undermining Promise to Run a Different Kind of Campaign.”

And on Friday, Clinton’s top pollster, Joel Benenson, charged that Sanders was running “the most negative” Democratic primary campaign in history.

Huh? Are we watching the same campaign?

All of this sturm und drang is about a single Sanders ad released on Thursday that takes aim—implicitly—at the six-figure speaking fees that Clinton accepted from top Wall Street firms like Goldman Sachs after she left the State Department in 2013.

Is this a tougher, more negative ad than the hopeful, patriotic spot Sanders ran to the tune of Simon and Garfunkel’s “America”? Certainly. Is it an attack ad? No. As you can see, the narrator never mentions Clinton's name or even refers to an opponent or another Democratic candidate. The ad more subtlety drops in references to “Goldman Sachs,” “speaking fees,” and Washington politicians “bought and paid for.” It leaves it to viewers to make the connection to Clinton, which given the headlines and Sanders’ more-direct references at the Democratic debates, they surely will. In other words, it’s a classic primary-campaign ad.

Clinton should know: She ran plenty of them against Barack Obama in 2008, and if this year's race stays close, you can bet she’ll run them against Sanders as well, before long. In fact, several of Clinton’s ads in 2008 made even more direct attacks on Obama, putting to rest the specious claim that Sanders is running the most-negative campaign in history. (Benenson should know, too: He was Obama’s pollster eight years ago, and that campaign ran plenty of negative ads against Clinton.) To take one example, in April of 2008, Clinton ran an ad in Pennsylvania seizing on Obama's comments at a private fundraiser that people in small towns “cling to guns or religion” to explain their frustration. The ad featured video of voters calling Obama “insulting” and “out of touch” with voters. (While many Clinton ads from 2008 have been taken off YouTube, you can find a good repository at Stanford University’s Political Communication Lab.)

The real story here is that the Clinton campaign is pursuing the same strategy she tried to use, without success, against Obama. Sanders is running on a more economically populist version of the “new politics” campaign that Obama ran in 2008, and Clinton is looking for any morsel of hypocrisy in an effort to dent his image and cast him as the kind of traditional politician from whom voters are recoiling. By seizing on any hint of negativity, she’s also trying to force Sanders into a box of his own making, keeping him from drawing the kinds of direct contrasts he may need to make in order to win. Never mind for the moment the many studies showing that negative advertising is actually quite effective, and whether voters actually care about the “negativity debate” is another question.

It’s a tricky game for both candidates. Sanders says he won’t run “negative ads,” but he will draw “a contrast” with Clinton on the issues. That can be a very blurry line, and politicians often use the word “contrast” as a euphemism to describe ads that are, in truth, quite nasty. “Let me tell you, I run vigorous campaigns,” Sanders said at that same opening press conference. Sanders is benefitting from the fact that nothing he’s said about Clinton compares to the mud-slinging going on in the Republican primary. And so far, Sanders is the one looking artful while Clinton risks coming off as desperate. But that can change as fast as the votes are counted in Iowa.