The Trump White House’s legal strategy to keep top officials from testifying in impeachment proceedings is now focused on exploiting the slow pace of the legal system.

The goal of the run-out-the-clock approach is to tie up in courts the fight over whether top officials from the National Security Council, Office of Management and Budget and White House chief of staff’s office can appear before Congress — all while asserting expansive powers for the office of the president.

Court battles could last months, bringing the stand-off between Congress and the White House closer to the 2020 primary races. Democrats have long said they want to move quickly on the impeachment inquiry and keep it narrowly focused, with House aides tentatively hoping to wrap up the inquiry before Christmas.