Liberal groups are desperately trying to mend fences to avoid a center-left contender becoming the party’s next standard-bearer. But, however unlikely, Tuesday night’s debate provides a platform for Sanders to respond in kind with an attack line pedaled by his supporters on social media.

“Here’s Bernie Sanders saying clearly that a woman could be elected president. This is in 1988, when Warren was still busy lying about being Native America so she could get into elite schools & was still busy voting for a Republican President who laughed about people dying of AIDS,” author Ashok Kumar tweeted with a video of Sanders.

Warren last year released DNA results revealing she had one Native American ancestor six to 10 generations ago. The move was an attempt to counter criticism, perpetuated by President Trump’s “Pocahontas” moniker, that she professionally benefited from claiming to have Cherokee and Delaware Tribe of Indians lineage based on family folklore. The Boston Globe reported last September that Harvard University and Warren’s other former law school employers didn’t factor her minority status into their decisions to hire her.

The offensive plays into Warren’s record of weaving slightly shifting stories on the campaign trail, similar to the narrative that formed around Al Gore in 2000.

Other than her Native American assertions, which she’s been defending since her inaugural Senate race in 2012, she’s faced scrutiny this cycle for allegations she was fired from her first teaching job because she was “visibly pregnant” and for giving different reasons for why she applied to law school, but then didn’t practice law. Questions have also been raised about a #MeToo anecdote involving a University of Houston colleague, retelling how he lunged at her during a wake for a colleague in 1997.

Gary Pearce, a Democratic strategist, said Warren’s discrepancies might become an issue as the party weighs her electability against Trump.

“It might put a chink in her armor in the primary,” he told the Washington Examiner, adding “a larger concern” was whether she was “too much ‘big government liberal’ to beat Trump. Obviously, people care about the impact the top of the ticket has in November, which is huge.”

Yet other Democrats are calling for a ceasefire before the six qualifying hopefuls take the debate stage in Des Moines.

“Look, there will be harsh disputes as the primary heats up. My entire focus is on electing principled progressives at the national and state level. The future depends on building a massive progressive wave. Any Dem sabotaging that needs to think twice,” strategist Peter Daou tweeted.