Mueller Hearing to Air Evidence of Trump Wrongdoing If so, then then Nadler and the Democrats are derelict of duty by not impeaching Trump. According to what Nadler says here, there's no need for Mueller to testify - If what Nadler says is true, a vote on impeachment should have already happened. Why are the Democrats derelict of their duties? Why have they violated their oaths of office? Why aren't liberals and Democrats SCREAMING for them to impeach?