Twice-failed presidential candidate Hillary Clinton on Wednesday attributed the shortfalls of failed female presidential candidates — Sens. Amy Klobuchar (D-MN), Kamala Harris (D-CA), and most recently Elizabeth Warren (D-MA) — to “unconscious” gender bias.

Clinton spoke to Vanity Fair, ahead of the New York premiere of her documentary Hillary, about the Democrat primary race and offered insight on the females in the race, who ultimately failed to resonate with Democrat primary voters.

She called Warren, who dropped out of the race Thursday morning, “an incredible candidate” but mused that “unconscious” gender bias likely affected all of the women who threw their hats in the ring.

“I think we made some progress, but there still was a lot of the unconscious bias and the gendered language that has been used around the women candidates,” Clinton told the magazine. “I think it affected all of the women that ran.”

“She has really set the bar for putting out policies that would make a big difference in lives of Americans,” Clinton said of Warren, referring to her as an “incredible and effective competitor.”

Vanity Fair notes the documentary aims to serve as a “means of illuminating the biases that hamper female politicians, highlighting how Clinton has stared them down through her decades in the spotlight (to mixed effect)—and positing what needs to be done to achieve real ideological progress.”

Clinton believes the shift, or real change, will take place after someone breaks “that highest, hardest glass ceiling” and becomes the first woman president.

While the former secretary of state, famously issued a host of reasons she lost the 2016 election to President Trump, sexism often topped her list. She even blasted Trump’s debate style, declaring it was fundamentally “imbued with sexism.”

“If you watched the way Trump debated me, it was imbued with sexism. Making fun of me for preparing—that’s the old like, ‘Oh, yeah, the girl in the class who is always prepared, I don’t need to be prepared,'” she told CBS News’s Sunday Morning in 2018.

The year prior, Clinton proclaimed that “sexism and misogyny” were “endemic” in American society.