Question: who was serving as the us president just prior to the 1860 election
[{'answer': 'James Buchanan Jr.', 'provenance': [{'wikipedia_id': '19732383', 'title': 'James Buchanan', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]