House Democrats have filed a lawsuit to force former White House counsel Don McGahn to testify.
The committee argues it needs to hear from him to determine whether it should consider articles of impeachment against President Trump.
The committee calls McGahn the “most important witness,” in its investigation into possible obstruction of justice by Trump.
The lawsuit outlines exactly how the judiciary committee might use McGahn’s testimony in an impeachment proceeding.
The committee subpoenaed McGahn in April but the white house blocked it, claiming McGahn had “absolute” immunity.