FBI Director James Comey’s announcement Friday that the bureau had reopened its investigation of the classified information in Hillary Clinton’s emails could scramble the already-tightening battle for control of the White House and Senate.

“Two Fridays before Election Day leaves a lot of time for people still deciding and for voters to change their minds from what they may have been intending,” said Mark Serrano, a GOP strategist who has worked on presidential campaigns since 1987. “There is plenty of time, because there was already a shift underway, and so I think that shift will likely pick up speed.”