Question: who was president when congress declared war on spain
[{'answer': 'President McKinley', 'provenance': [{'wikipedia_id': '28265', 'title': 'Spanish–American War', 'start_paragraph_id': 29, 'start_character': 0, 'end_paragraph_id': 29, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Path to war.:US response.\n'}]}, {'provenance': [{'wikipedia_id': '28265', 'title': 'Spanish–American War', 'start_paragraph_id': 39, 'start_character': 307, 'end_paragraph_id': 39, 'end_character': 1058, 'bleu_score': 0.5860795421264531, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2632823345680119674}, 'section': 'Section::::Path to war.:Declaring war.\n'}]}]