Brian Miller, the Trump White House lawyer nominated to oversee the coronavirus financial relief effort, broadly refused Tuesday to address the president’s recent moves to oust government watchdogs who criticized the administration, as Senate Democrats pressed him repeatedly with questions about his independence.

Testifying through a blue mask, Miller cited “ethical obligations” as barring him from discussing his work as a White House lawyer under the Trump administration, a role Senate Democrats argued should have disqualified him from being picked to serve as the special inspector general for pandemic recovery.