Question: what us supreme court justice presides over presidential impeachment proceedings
[{'answer': 'the Chief Justice', 'provenance': [{'wikipedia_id': '31739', 'title': 'Chief Justice of the United States', 'start_paragraph_id': 6, 'start_character': 199, 'end_paragraph_id': 6, 'end_character': 216, 'bleu_score': 1.0, 'section': 'Section::::Origin, title, and appointment to office.\n'}]}]