Minority Leader Nancy Pelosi stopped short on Wednesday of demanding Secret Service Director Julia Pierson resign, but called for an “independent investigation” into the disturbing protocol breaches within the agency that she said were “inexcusable.”

“The challenge may be more than one person,” the California Democrat told reporters at a press conference on Capitol Hill. “Whether she [resigns] or not, I think we need an independent investigation. Her leaving doesn’t end the need to learn more.”