https://www.youtube.com/embed/LqLfvQfuvsA

Campaigning in the age of social media means that sometimes you'll be two days away from the South Carolina presidential primary—a race you're expected to win handily—and suddenly a hashtag will start trending on Twitter that calls into question every inconsistency of your decades-long career in politics.

That was the case for Hillary Clinton Thursday morning when the hashtag #WhichHillary started trending, eliciting more than 88,000 tweets by 1 pm ET. The hashtag, which has been used intermittently on social media to point out times that Clinton has supposedly flip-flopped on issues, gained steam after an altercation between Clinton and Black Lives Matter activist Ashley Williams at a private fundraiser in South Carolina Wednesday.

Williams stood beside Clinton, holding a sign that included the hashtag and a quote: "We have to bring them to heel." The quote refers to a speech Clinton gave as First Lady in 1994, in which she referred to gang members as "super-predators."

"I'm not a super-predator, Hillary Clinton," Williams said, before being escorted out of the event. Video of the moment (posted below) soon went viral, as did the hashtag itself.

Now it's being used to challenge everything from Clinton's relationship with Wall Street to her record on gay marriage to her record on mass incarceration. But the hashtag isn't just being fueled by the Black Lives Matter movement. It's also getting a boost from Bernie Sanders' army of Twitter supporters.

The hashtag reflects a new reality for political campaigns. Even if Sanders has vowed not to go negative, his followers online haven't taken the same oath. Social media gives them the microphone to do it. For Clinton, the timing couldn't be worse, as both she and Sanders have been working to court black voters in the lead up to the South Carolina primary.

Still, with some polls showing that Clinton is leading Sanders in South Carolina 60 to 32 percent, it's unlikely even the strongest Twitter army could thwart this win.