Washington ? A seasoned Democratic political operative will guide President Barack Obama’s eventual Supreme Court nominee on Capitol Hill, where the Senate’s top Republican on Sunday refused to rule out a filibuster.

Stephanie Cutter is expected to leave her job as an adviser to Treasury Secretary Timothy Geithner and move next door to the White House, an administration official said. The official spoke on the condition of anonymity to discuss personnel decisions and strategy.

Cutter, a veteran of presidential campaigns and Senate politics, is expected to coordinate the announcement and confirmation hearings for Obama’s pick to replace Justice David Souter, who is retiring. Democrats control the Senate, although the White House does not expect an automatic confirmation for the lifetime appointment.

Republicans are keeping all paths open. Sen. Mitch McConnell of Kentucky said he would not rule out a filibuster. During confirmation hearings for Justices Samuel Alito and John Roberts, McConnell opposed using the procedural move, which could indefinitely delay votes on a nominee.