Question: when was the line item veto ruled unconstitutional
[{'answer': '1998', 'provenance': [{'wikipedia_id': '752054', 'title': 'Clinton v. City of New York', 'start_paragraph_id': 1, 'start_character': 43, 'end_paragraph_id': 1, 'end_character': 47, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '752054', 'title': 'Clinton v. City of New York', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 534, 'bleu_score': 0.9792717993254391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17888042996371306252}, 'section': 'Section::::Abstract.'}]}]