For any reasonable cause to be entered on the journals of each House, which may or may not be sufficient grounds for impeachment, the justices of the Supreme Court, the judges of the court of appeals and the judges of the district courts must be removed from office on the vote of two thirds of the members elected to each branch of the Legislature. The justice or judge complained of must be served with a copy of the complaint against him, and have an opportunity of being heard in person or by counsel in his defense. No member of either branch of the Legislature is eligible to fill the vacancy occasioned by such removal.