Activists are calling for nationwide protests Thursday over fears that President Donald Trump is derailing the Mueller investigation.

On Wednesday, Attorney General Jeff Sessions was ousted, putting his replacement, Acting Attorney General Matthew Whitaker, in charge of the probe into Russian election interference and potential collusion by the Trump campaign. Whitaker has been outspoken in the past about his objection to the scope of Mueller’s investigation, and in 2017 outlined a scenario to reduce the probe’s funding “so low that his investigation grinds to almost a halt.”