Question: what idea was used to justify u.s. foreign policy during the cold war era
[{'answer': 'containment', 'provenance': [{'wikipedia_id': '7564', 'title': 'Foreign policy of the United States', 'start_paragraph_id': 18, 'start_character': 594, 'end_paragraph_id': 18, 'end_character': 605, 'bleu_score': 1.0, 'section': 'Section::::Historical overview.:20th century.:Cold War.\n'}]}, {'provenance': [{'wikipedia_id': '7564', 'title': 'Foreign policy of the United States', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 909, 'bleu_score': 0.9541724938233, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4253228236037708972}, 'section': 'Section::::Historical overview.:20th century.:Cold War.\n'}]}]