When Sessions recused himself from Trump campaign-related investigations in March 2017, Deputy Attorney General Rod Rosenstein stepped in to oversee the probe into whether the Trump campaign was involved in Russian election meddling in 2016. But acting Attorney General Matthew Whitaker hasn't stepped away from any investigations, and a Department of Justice spokesperson confirmed to NBC News that "the acting attorney general is in charge of all matters under the purview of the Department of Justice." With Sessions out as attorney general as of Wednesday afternoon, Whitaker is now poised to take over for Rosenstein in the investigation's top spot.
Shortly after Whitaker's promotion, Senate Minority Leader Chuck Schumer issued a statement calling on Whitaker to recuse himself from Mueller's probe. Schumer, like other Democrats who echoed his demand, likely noted Whitaker's very public stances on the Russia investigation. Before he joined the DOJ, Whitaker authored a CNN column specifically saying "Mueller's investigation into Trump is going too far," and suggested to CNN that an attorney general could cut Mueller's budget to slow his investigation.